Ratio

Ratio

Noun · /ˈreɪʃiəʊ/ · a relationship between two quantities expressed as a proportion

Definition

A ratio is a mathematical relationship that expresses how many times one value contains or is contained by another. Written as 3:1, 3 to 1, or the fraction three-over-one, a ratio describes the relative size of two or more quantities. It does not tell you the actual amounts — only their relationship to each other. A school with a pupil-to-teacher ratio of 20:1 might have 200 pupils and 10 teachers, or 60 pupils and 3 teachers. The ratio is the same either way.

Origin

From Latin ratio, meaning a reckoning, an account, a calculation — from ratus, past participle of reri (to reckon, to think). The word entered English in the 17th century through mathematics and philosophy.