- (of a person or personal characteristics) Healthy or balanced intellectually; exhibiting reasonableness.
- (chemistry) Expressing the type, structure, relations, and reactions of a compound; graphic; said of formulae.
- Logically sound; not contradictory or otherwise absurd.
"His statements were quite rational."
- (mathematics, arithmetic, not comparable) Of an algebraic expression, capable of being expressed as the ratio of two polynomials.
- Capable of reasoning.
"Man is a rational creature."
- (mathematics, arithmetic, number theory, not comparable) Of a number, capable of being expressed as the ratio of two integers.
"¾ is a rational number, but √2 is an irrational number."
- A rational being.
- (mathematics) A rational number: a number that can be expressed as the quotient of two integers.
"The quotient of two rationals is again a rational."