NOTE 1 The concept of "quantity" is defined in IEC 60050-111 and in the International Vocabulary of Basic and General Terms in Metrology (VIM).

NOTE 2 The vector defining a vector quantity is generally a unit vector in the usual two- or three-dimensional geometrical space. A vector quantity can then be represented as an oriented line segment characterized by its point of acting, its direction and its magnitude, where the magnitude is a non-negative number multiplied by a unit of measurement. The components are also the product of a numerical value and the unit. Examples of vector quantities are: velocity, force, electric field strength.

NOTE 3 A vector quantity may be considered either as attached to a point of acting (localized or bound vector), or as having any point of acting on a straight line parallel to it (sliding vector), or as having any point of acting in the space (free vector).

NOTE 4 Operations defined for vectors apply to vector quantities. For example, the product of a scalar quantity p and the vector quantity $Q=qe$ is the vector quantity $pQ=pqe$, where e is a unit vector.