The crossword solution for the term PRO ___ (PROPORTIONATE) is RATA, a four-letter word. Rata is a Latin word meaning 'in proportion' or 'in due measure'. It is often used in mathematics and science to describe a relationship between two or more quantities that are proportional to each other. In other words, when one quantity increases, the other decreases in the same ratio. For example, if one quantity doubles, the other quantity will also double.