rational
UK[ˈræʃnəl]US[ˈræʃnəl]
adj
Based on reason or logic, not emotions or feelings.
adj
Able to think clearly and make decisions based on reason.
adj
(Mathematics) Expressible as a ratio of whole numbers.
Morpheme Breakdown
ratio
nal
ratio
reason, calculation
nal
adjective suffix
Etymology
The word 'rational' originates from the Latin 'rationalis', meaning "of or belonging to reason," which itself derives from 'ratio' (genitive 'rationis'), signifying "reckoning, calculation, reason." The Latin 'ratio' stems from the past participle stem 'ratus' of the verb 'reri', "to reckon, think." This etymological journey reflects a core progression from the concrete act of mathematical calculation to the abstract faculty of logical reasoning. Thus, the modern meanings—from logical thought to expressible fractions—are directly tied to this ancient concept of measured reckoning.
Analysis
Structure: ratio (reason, calculation) + nal (adjective suffix)
'ratio' is from Latin 'ratio' (reckoning, reason, calculation). '-nal' is an English adjective-forming suffix, a variant of '-al', from Latin '-alis'.
Examples
There must be a rational explanation for what happened.
In a crisis, it's important to stay calm and rational.
The number 0.75 is a rational number because it can be written as 3/4.