/ ˈreɪʃiəʊ; NAmE -oʊ/ noun
( pl. -os ) ratio (of A to B) the relationship between two groups of people or things that is represented by two numbers showing how much larger one group is than the other :
What is the ratio of men to women in the department?
The school has a very high teacher-student ratio.
The ratio of applications to available places currently stands at 100:1.
••
WORD ORIGIN
mid 17th cent.: from Latin , literally reckoning , from rat- reckoned, from the verb reri .