1.Definition: capable of being expressed as a quotient of integers

"Rational numbers"

2.Definition: consistent with or based on or using reason

"Rational behavior", "A process of rational inference", "Rational thought"

3.Definition: having its source in or being guided by the intellect (as distinguished from experience or emotion)

"A rational analysis"

4.Definition: of or associated with or requiring the use of the mind

"The triumph of the rational over the animal side of man"

Related Adjective(s):intellectual, noetic