Pronunciation: (pru-pôr'shu-nl, -pōr'-),[key] —adj. 1. having due proportion; corresponding.
2. being in or characterized by proportion.
3. of, pertaining to, or based on proportion; relative.
4. Math. a. (of two quantities) having the same or a constant ratio or relation: The quantities y and x are proportional if y/x = k, where k is the constant of proportionality. b. (of a first quantity with respect to a second quantity) a constant multiple of: The quantity y is proportional to x if y = kx, where k is the constant of proportionality.