[ree-uh-pawr-shuh n-muh nt, -pohr-]
  1. the act of redistributing or changing the apportionment of something.
  2. the redistribution of representation in a legislative body.

Origin of reapportionment

First recorded in 1930–35; reapportion + -ment Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for re-apportionment

also reapportionment, 1800, American English, from re- + apportionment.

Online Etymology Dictionary, © 2010 Douglas Harper