verb (used without object), pro·rat·ed, pro·rat·ing.
verb (used with object), pro·rat·ed, pro·rat·ing.
Origin of prorate
Word Origin for prorate
also pro-rate, "divide proportionally," 1860, American English, verb derived from Latin pro rata (parte) (see pro rata). Related: Prorated; prorating.
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.