Main Entry:

¹ra·tio·nal

Pronunciation:

\ˈrash-nəl, ˈra-shə-n^əl\

Function:

adjective

Etymology:

Middle English racional, from Anglo-French racionel, from Latin rationalis, from ration-, ratio

Date:

14th century

1 a: having reason or understanding b: relating to, based on, or agreeable to reason : reasonable <a rational explanation> <rational behavior>2: involving only multiplication, division, addition, and subtraction and only a finite number of times3: relating to, consisting of, or being one or more rational numbers <a rational root of an equation>

— ra·tio·nal·ly adverb

— ra·tio·nal·ness noun