"A unit which is a standard measure of the quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons." [WordNet:WordNet]
"A unit which is a standard measure of the work done per unit charge as a charge is moved between two points in an electric field." [Wikipedia:Wikipedia]
"A unit which is a standard measure of the rate of movement. Speed is measured in the same physical units of measurement as velocity, but does not contain the element of direction that velocity has. Speed is thus the magnitude component of velocity." [Wikipedia:Wikipedia]