Ratio

How to spell ratio

5 letters · 3 syllables

How to pronounce ratio

Say the part in capitals loudest.

What does ratio mean?

1. nounThe proportional relationship between two amounts, showing how many times one value contains or is contained within the other.

Ratio in a sentence

• The recipe uses a two to one ratio of flour to sugar.

• The company aims to improve its debt to equity ratio this year.

Where does ratio come from?

Language of origin: Latin

This word comes directly from the Latin noun ratio, which meant a reckoning, a calculation, or an account, and by extension also reason or judgement. It was built on the verb reri, 'to reckon' or 'to think', whose past participle stem rat- supplied the noun. English took ratio over wholesale in the early 1600s, first in mathematics and bookkeeping for the proportional relationship between two quantities, keeping the Latin spelling intact. The same Latin root fans out into a surprisingly large family of English words, including reason, rational, rate, and even ration, all of which trace back to that idea of measured calculation. The spelling trap lies in the ending: the -tio is pronounced like 'show', so writers sometimes want to add letters or spell it 'ratioh' or 'rashio', when in fact the clean Latin -tio is all that is needed.

How the word is built

• rat- (from Latin reri, to reckon or calculate)
• -io (Latin noun suffix forming abstract nouns)