pro ra‧ta /prəʊ ˈrɑːtə $ proʊ ˈreɪtə/ adjective [only before noun] especially British English
[Date: 1500-1600; Language: Latin; Origin: 'for the rate']
a payment or share that is pro rata is calculated according to how much of something is used, how much work is done etc:
Fees are calculated on a pro rata basis.
—pro rata adverb

[TahlilGaran] Dictionary of Contemporary English ▲