term:

Apportion

apportion vt

: to make a usually proportionate division or distribution of (an amount due) according to a plan: as
a : to divide (an amount due in tax or other liability) among the parties responsible for respective shares of the payment compare contribution
b : to assign (a portion of the consideration agreed to in a contract) as payment for the other party's partial performance
c : to distribute (corporate dividends) based on some proportion
d : to assign (legislative representatives and taxes) among the states as provided by law
ap·por·tion·able adj

ap·por·tion·ment n

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.