The first order [[../Math/Derivative|Derivative]] of [[Position]], how [[Speed|fast]] something is going and in what [[../Math/Vector|Direction]]. Velocity is measured over [[Displacement]]. $\huge \vec v = \frac{{p_{1} - p_{0}}}{t} $ or for non constant [[Acceleration]]: $\huge \vec v(t) = \lim_{ \d t \to \infty } \frac{{\vec p (t+ \d t) - \vec p(t)}}{\d t} $