Pro rata means in proportion. If money is given out pro rata, everyone gets a fair share.
Pro rata is a Latin term meaning "in proportion," so when you see it you know that something is being distributed or done in equal or fair proportions. If food is distributed pro rata, the greater number of people will get a greater amount of food. A pro rata tax will be influenced by how much money someone makes: the more they make, the higher rate of tax they'll pay. Anything done pro rata is usually considered fair.