Use this tag for questions and problems involving vectors, e.g., in an Euclidean plane or space. More abstract questions, might better be tagged vector-spaces, linear-algebra, etc.

A classical example of a vector spaces is $\mathbb{R}^n$, the $n$-tuples of real numbers (with the usual addition and scalar multiplication).

Elements of these spaces are often referred to as vectors.

Various vector spaces admit notions of lengths (and angles), often introduced via equipping the space with an inner product. In such a context a vector can be thought of as a quantity having a direction and magnitude.

This tag is mostly intended for questions involving vectors in a rather concrete form, e.g., finding intersection of lines and planes, determining projections, and other computations and problems involving vectors in a concrete way.

More structural and algebraic questions on vectors, are often better tagged vector-spaces and/or linear-algebra.

See here for more information.