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definitions

prorate

[proh-reyt, proh-reyt]
verb (used without object), pro·rat·ed, pro·rat·ing.
  1. to make an arrangement on a basis of proportional distribution.
verb (used with object), pro·rat·ed, pro·rat·ing.
  1. to divide, distribute, or calculate proportionately.

Origin of prorate

1855–60, Americanism; partial translation of pro rata
Related formspro·rat·a·ble, adjectivepro·ra·tion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for proration

prorate

verb
  1. mainly US and Canadian to divide, assess, or distribute (something) proportionately
Derived Formsproratable, adjectiveproration, noun

Word Origin for prorate

C19: from pro rata
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for proration
n.

1893, noun of action from prorate (v.).

prorate

v.

also pro-rate, "divide proportionally," 1860, American English, verb derived from Latin pro rata (parte) (see pro rata). Related: Prorated; prorating.

Online Etymology Dictionary, © 2010 Douglas Harper
proration in Culture

prorate

To divide or distribute a sum of money proportionately. For example, if one owned an automobile for only three months, an insurance company would prorate the annual premium by charging only one-quarter of it.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.