Anniversary
An anniversary is the date on which an event took place or an institution was founded in a previous year, and may also refer to the commemoration or celebration of that event. The word was first used for Catholic feasts to commemorate saints.
Most countries celebrate national anniversaries, typically called national days. These could be the date of independence of the nation or the adoption of a new constitution or form of government. There is no definite method for determining the date of establishment of an institution, and it is generally decided within the institution by convention. The important dates in a sitting monarch's reign may also be commemorated, an event often referred to as a "jubilee".
Names
 Birthdays are the most common type of anniversary, on which someone's birthdate is commemorated each year. The actual celebration is sometimes moved for practical reasons, as in the case of an official birthday or one falling on February 29.
 Wedding anniversaries are also often celebrated, on the same day of the year as the wedding occurred.
 Death anniversaries.
The Latin phrase dies natalis (literally "birth day") has become a common term, adopted in many languages, especially in intellectual and institutional circles, for the anniversary of the founding ("legal or statutory birth") of an institution, such as an alma mater (college or other school). In ancient Rome, the [dies] Aquilae natalis was the "birthday of the eagle", the anniversary of the official founding of a legion.
Anniversaries of nations are usually marked by the number of years elapsed, expressed with Latin words or Roman numerals.
Numerical
Latin terms for anniversaries are mostly straightforward, particularly those relating to the first thirty years (1–30), or multiples of ten years (30, 40, 50, 60, 70 etc.), or multiples of centuries or millenniums (100, 200, 300, 1000, 2000, 3000, etc.) In these instances, the name of the anniversary is generally derived from the Latin word(s) for the respective number of years. When anniversaries relate to fractions of centuries (125, 150, 175, 225 years—i.e. 1.25, 1.5, 1.75, and 2.25 centuries), the situation is not as simple.
Roman fractions were based on a duodecimal system. From 1⁄12 to 8⁄12 they were expressed as multiples of twelfths (uncia "twelfth"; the source of the English words inch and ounce) and from 9⁄12 to 11⁄12 they were expressed as multiple twelfths less than the next whole unit—i.e. a whole unit less 3⁄12, 2⁄12 or 1⁄12 respectively. There were also special terms for quarter (quadrans), half (semis), and threequarters (dodrans). Dodrans is a Latin contraction of dequadrans which means "a whole unit less a quarter" (de means "from"; quadrans means "quarter"). Thus for the example of 175 years, the term is a quarter century less than the next whole (bi)century or 175 = (−25 + 200).[1]
In Latin, it seems that this rule did not apply precisely for 1+1⁄2. While secundus is Latin for "second", and bis for "twice", these terms are not used such as in sesquisecundus. Instead sesqui (or ses) is used by itself.
Anniversary  Latinderived term  Other terms  Comments 

1 Day  Datal  
1 Week  Weekal  
1 Month  Monthal  
3 months  Quarteral  
6 months  Semiannual  'Biannual' means twice in a year, but is also commonly used incorrectly to mean once every two years ('biennial').  
Biannual  
1 year  Annual  Paper  
2 years  Biennial  Cotton  'Biennial' means once every two years, but is also commonly used incorrectly to mean twice in a year ('biannual'). 
3 years  Triennial  Leather  
4 years  Quadrennial  Linen  
5 years  Quinquennial  Wood  
6 years  Sexennial  Iron  
7 years  Septennial  Wool  
8 years  Octennial  Bronze  
9 years  Novennial  Copper  
10 years  Decennial  Tin Aluminum 

Denary  
11 years  Undecennial  Steel  
12 years  Duodecennial  Silk  
121⁄2 years  Parsley  A humorous or mock wedding anniversary celebrated in Germany and the Netherlands where everyone needs to wear something green  
13 years  Tredecennial  Lace  
14 years  Quattuordecennial  Ivory  
15 years  Quindecennial  Crystal  
16 years  Sexdecennial  Sapphire  Sapphire is separately used for other anniversaries 
17 years  Septdecennial  Orchid  
18 years  Octdecennial  Quartz  
19 years  Novdecennial  Jade  
20 years  Vigintennial  China/Porcelain  
Vicennial  
Vicenary  
21 years  unvigintennial  
22 years  duovigintennial  
23 years  trivigintennial  
24 years  quadrivigintennial  
25 years  Quadranscentennial  Silver  
26 years  sexavigintennial  
27 years  septvigintennial  
28 years  octovigintennial  
29 years  Nonavigintennial  
30 years  Tricennial  Pearl  
Tricenary  
35 years  Quintricennial  Coral  
40 years  Quadragennial  Ruby  
Quadragenary  
45 years  Quinquadragennial  Sapphire  
50 years  Semicentennial  Golden  Previously, "jubilee" by itself was used to indicate celebrations at 50 year intervals 
Quinquagenary  
55 years  Quinquinquagennial  Emerald  
Quinquinquagenary  
60 years  Sexagennial  Diamond  Diamond is separately used for the 75th anniversary, its use for 60th years being popularized by Diamond Jubilee of Queen Victoria 
Sexagenary  
65 years  Quinsexagennial  Sapphire  Sapphire is separately used for other anniversaries 
70 years  Septuagennial  Platinum  
Septuagenary  
75 years  Semisesquicentennial  Diamond  Diamond is separately used for the 60th anniversary 
Demisesquicentennial  
80 years  Octogintennial  Oak  
Octogenary  
85 years  quinoctogennial  
90 years  Nonagintennial  Granite  
Nonagenary  
95 years  quinnonagennial  
100 years  Centennial  
Centenary  
110 years  decaCentennial  
120 years  bidecaCentennial  
125 years  Quasquicentennial  Term is broken down as quasqui (and a quarter) centennial (100 years). Quasqui is a contraction from quadrans "a quarter" plus the clitic conjunction que "and". The term was coined by Funk and Wagnalls editor Robert L. Chapman in 1961.[2]  
130 years  tridecaCentennial  
140 years  quadridecaCentennial  
150 years  Sesquicentennial  Term broken down as sesqui (one and a half) centennial (100 years)  
160 years  sexadecaCentennial  
170 years  septdecaCentennial  
175 years  Dodransbicentennial  Dodrans is a Latin contraction of dequadrans which means "a whole unit less a quarter" (de means "from"; quadrans means "quarter"). 175 years is a quarter century less than the next whole (bi)century (175 = 200 − 25).[1]  
Dodrabicentennial  Alternative Latin form of Dodransbicentennial  
Dequasbicentennial  Alternative Latin form of Dodransbicentennial  
Dosquicentennial  Dosquicentennial has been used in modern times and this is perhaps a modern contraction of "dequadrans".[1]  
Demisemiseptcentennial  Probably a modern coined term: demisemiseptcentennial; literally onehalf (demi) × onehalf (semi) × seven (sept) × 100 years (centennial)—also demisemiseptcentenary.[3][4]  
Quartoseptcentennial  Probably a modern coined term: quartoseptcentennial; literally onequarter (quarto) × seven (sept) × 100 years (centennial)—also quartoseptcentenary.[3]  
Terquasquicentennial  A coined word for an anniversary of 175 years, but the elements of the word literally refer to an anniversary of 375 years, as follows: ter (3) × quasqui (11⁄4) × centennial (100 years)  
Septaquintaquinquecentennial  Suggested by lexicographer Robert L. Chapman to William Safire; first appeared in Safire's column, "On Language" (The New York Times Magazine, February 12, 1995). It is a coined word for an anniversary of 175 years, but the elements of the word literally refer to an anniversary of 35,000 years, as follows: septaquinta (70) × quinque (5) × centennial (100 years)  
180 years  octodecaCentennial  
190 years  nonadecaCentennial  
200 years  Bicentennial  
Bicentenary  
225 years  Quasquibicentennial  
250 years  Sestercentennial  To express 2+1⁄2 in Latin it would be expressed as "halfthree". The term relates to being halfway [from the second] to the third integer. In Latin this is "Sestertius", which is a contraction of semis (halfway) tertius (third)—hence Sestercentennial.[1]  
Semiquincentennial  Probably a modern coined term: semi (half) × quin (5) × centennial (100 years) = 250 years. Used by Brown University in 2015.[5]  
Bicenquinquagenary  Used by Princeton University in 1996, Reading, Pennsylvania in 1998, and Washington and Lee University in 1999.[6] It is a coined word for an anniversary of 250 years: bi (2) × cen(t) (100) + quinquagenary (50 years).  
Quartermillennial  [7]  
Quadransmillennial  From quadrans (quarter) x millennial (1000 years).  
275 years  dodranstricentennial  
300 years  Tercentenary  
Tercentennial  
Tricentenary  
Tricentennial  
325 years  quasquitricentennial  
350 years  Sesquarcentennial  Sesquarcentennial is a modern coined term; sesquarcentennial for 350 years is deduced here from the "Sestertius" definition for 250 years above. For 350 years it relates to being halfway from the third to the fourth integer; thus a contraction of semis (halfway) and quartus (fourth); hence Sesquarcentennial. Semiseptcennial is probably a modern coined term: semi (half) × sept (7) × cen(t) (100) × centennial (350 years).  
Semiseptcentennial  
375 years  dodransquadricentennial  
400 years  Quadricentennial  
Quadricentenary  
Quatercentenary  
425 years  quasquiquadricentennial  
450 years  Sesquincentennial  
475 years  dodransquincentennial  
500 years  Quincentenary  
Quincentennial  
550 years  Sessexacentennial  
600 years  Sexcentenary  
Sexacentennial  
650 years  Sesseptcentennial  
700 years  Septcentennial  Probably a coined term; earliest known use in March 1988.[8] Chiang Mai Septcentennial Stadium (Chiang Mai, Thailand) was completed in 1991.[9]  
Septuacentennial  
750 years  Sesoctocentennial  
800 years  Octocentenary  
Octocentennial  
850 years  Sesnonacentennial  
900 years  Nonacentennial  
950 years  Sesdecacentennial  
1000 years  Millennial  
1100 years  centimillennial  
1200 years  bicentimillennial  
1300 years  tricentimillennial  
1400 years  quadricentimillennial  
1500 years  Sesquimillennial  Term broken down as sesqui (one and a half) millennial (1000 years)  
1600 years  sexacentimillennial  
1700 years  septcentimillennial  
1800 years  octocentimillennial  
1900 years  nonacentimillennial  
2000 years  Bimillennial  
2100 years  centibimillennial  
2200 years  duocentibimillennial  
2300 years  tricentibimillennial  
2400 years  quadricentibimillennial  
2500 years  sesquibimillennial  
2600 years  sexacentibimillennial  
2700 years  septcentibimillennial  
2800 years  octocentibimillennial  
2900 years  nonacentibimillennial  
3000 years  Trimillennial  
3500 years  sesquitrimillennial  
4000 years  Quadrimillennial  
4500 years  sesquiquadrimillennial  
5000 years  Quinmillennial  
5500 years  sesquiquinmillennial  
6000 years  sexamillennial  
6500 years  Sesquisexamillenial  
7000 years  septmillennial  
7500 years  sesquiseptmillennial  
8000 years  octomillennial  
8500 years  sesquioctmillennial  
9000 years  nonamillennial  
9500 years  Sesquinonamillenial  
10,000 years  Decamillennial  
11,000 years  unDecamillennial  
12,000 years  doDecamillennial  
13,000 years  treDecamillennial  
14,000 years  quattuordecamillennial  
15,000 years  quindecimillennial  
16,000 years  sexaDecamillennial  
17,000 years  septDecamillennial  
18,000 years  octoDecamillennial  
19,000 years  nonadecamillennial  
20,000 years  Vigintimillennial  
25,000 years  Quinvigintimillennial  
30,000 years  trigintimillenial  
35,000 years  Quinteigintimillennial  
40,000 years  Quadragintimillennial  
45,000 years  Quinquadragintimillenial  
50,000 years  Quinagintimillenial  
60,000 years  Sexagintimillenial  
70,000 years  Septagintimillenial  
80,000 years  Octagaintimillenial  
90,000 years  nonagintimillenial  
100,000 Years  Centimillenial  
200,000 Years  bicentimillenial  
300,000 Years  tricentimillenial  
400,000 Years  quadricentimillenial  
500,000 Years  quincentimillenial  
1,000,000 Years  Megannual  From megannum  
2,000,000 Years  bimegannual  
3,000,000 Years  trimegannual  
5,000,000 Years  quinmegannual  
10,000,000 Years  Decamegannual  
20,000,000 Years  duoDecamegannual  
50,000,000 years  quindecamegannual  
100,000,000 Years  centimegannual  
250,000,000 Years  sesquibicentimegannual  
500,000,000 Years  quincentimegannual  
1,000,000,000 years  Gigannual  
5,000,000,000 years  quinGigannual  
10,000,000,000 years  decaGigannual  
100,000,000,000 years  centiGigannual  
1,000,000,000,000 Years  Terannual  
10^15 Years  Petannual  
10^18 Years  Exannual  
10^21 years  Zettannual  
10^24 years  Yottannual  
10^27 Years  Ronnannual  
10^30 years  Quettannual  
10^33 Years  Quetkilannual  
10^36 years  Quetmegannual  
10^39 years  Quetgigannual  
10^42 years  Quetterannual  
10^45 years  Quetpetannual  
10^48 years  Quetexannual  
10^51 years  Quetzettannual  
10^54 years  Quetyottannual  
10^57 years  Quetronnannual  
10^60 years  Quetquetannual / Duetannual  
10^63 Years  Duetkilannual  
10^100 years  Googannual  
10^303 years  Centilliannual 
Symbols
Many anniversaries have special names. Etiquette in Society, in Business, in Politics and at Home by Emily Post, published in 1922, contained suggestions for wedding anniversary gifts for 1, 5, 10, 15, 20, 25, 50, and 75 years.[10] Wedding anniversary gift suggestions for other years were added in later editions and publications; they now comprise what is referred to as the "traditional" list. Generally speaking, the longer the period, the more precious or durable the material associated with it.
There are variations according to some national traditions. There exist numerous partially overlapping, partially contradictory lists of anniversary gifts (such as wedding stones), separate from the 'traditional' names. The concepts of a person's birthday stone and zodiac stone, by contrast, are fixed for life according to the day of the week, month, or astrological sign corresponding to the recipient's birthday.
See also
References
 "SA 175th Jubilee". Clipper Ship 'City of Adelaide'. Archived from the original on 27 November 2013. Retrieved March 8, 2011.
So the name for a 175th anniversary? For now it is really up to the preference of the reader. One day one of these terms may make its way into popular usage, become accepted, and find a place in a dictionary.
 Chapman, Robert L. (February 1965). "The History of "Quasquicentennial"". American Speech. 40 (1): 53–57. doi:10.2307/454178. ISSN 00031283. JSTOR 454178.
It is our policy to reply as courteously and helpfully as we can to such requests, and I answered Mr. Hatten on August 7, suggesting quasquicentennial. Since this is a history, I shall quote the letter in full: Dr. Wilfred Funk has passed your letter of July I on to us. We are happy to help, if you feel that you really want a new Latinate word meaning "one hundred and twentyfifth anniversary". The best model upon which to form the word is "sesquicentennial", meaning "one hundred and fiftieth anniversary". We need a first element meaning "plus a fourth", analogous with "sesqui" which means "plus a half". "Sesqui" is apparently formed from "semis que", meaning "and a half". Now, both "quarta" and "quadrans" mean "a fourth", so we may begin with either "quarta que" or "quadrans que". The trick is to combine and shorten one of these as "sesqui" was combined and shortened from "semis que". If we follow the model of "sesqui" very closely, retaining the stressed vowel and final "s" of "quadrans", we get the word "quasquicentennial". Combining and shortening in other ways we can also get "quadqui", "quansqui", "quarsqui", and perhaps several others. On the grounds that it is closest to the model and also probably the least ugly of the set, I would choose "quasquicentennial" (pronounced kwahskwee) as the new word. Of course, you may decide that you do not really want or need a new word. There is no point in proliferating them needlessly. I should add, perhaps, that this word would not appear in any of our dictionaries until it had established itself in wide currency, even if you should decide to use it. I hope we have been able to help you.
 "Under the Cupola". Neighbors of Batavia. July–August 2008. p. 29.
The etymology of "demisemiseptcentennial" is compared to "hemidemisemiquaver", a 64th note.
 "Pickle Barrel: 175thbirthday bash planned for Dillsburg." The PatriotNews (Mechanicsburg, Penn.), Wednesday, 18 June 2008.
 "Brown lowers the curtain on 15month semiquincentenary". Brown University. 20150611. Retrieved 20150611.
 McCleery, William (November 19, 1997). "The Meaning of the 250th". Princeton Alumni Weekly. Princeton University. Retrieved March 23, 2011.
Faster, it seems, than you can say "bicenquinquagenary", Princeton's 250th anniversary has come and gone.
 "A Memorial of the Celebration of the Two Hundred and Fiftieth Anniversary of the Settlement of the Town of Northampton, Massachusetts". City of Northampton. Archived from the original on January 27, 2013. Retrieved March 23, 2011.
 Kersten, Glenn (March 1988). "Naming the Anniversaries". Quidnunc. Archived from the original on 21 January 2005. Retrieved 22 May 2019.
 Architects 49: Selected and Current Work. (The Master Architect Series; 5.) Image Publishing Group, 2006. ISBN 9781876907099
 "22. The Day of the Wedding. Post, Emily. 1922. Etiquette". bartleby.com.