razionale

Razionale is an Italian adjective and, less commonly, a noun used to denote things that are based on reason or logic. Derived from Latin rationalis, itself from ratio (reason, calculation), razionale conveys that something follows a methodical, evidence-based, or logically coherent line of thought. In everyday language it describes thoughts, actions, or systems as sensible, well-founded, and governed by rational criteria, and it can be used to distinguish such approaches from impulsive or emotional ones.

In mathematics, the term has a precise technical meaning. A numero razionale, or rational number, is any number that can be expressed as the ratio of two integers p and q, with q not equal to zero. The set of rational numbers is typically denoted by the letter Q and includes all integers as fractions with denominator 1. Rational numbers are closed under addition, subtraction, multiplication, and division (except by zero) and are dense on the real number line, meaning that between any two real numbers there exists a rational number.

Beyond mathematics, razionale is used in philosophy, science, and everyday discourse to describe reasoning-based methods or explanations. It emphasizes justification, coherence, and evidence, as opposed to speculative or purely emotional considerations. In contrast with synonyms such as ragionevole (reasonable in a practical sense) or logico (strictly logical), razionale often carries a stronger connotation of systematic, rule-guided reasoning.

Related concepts include razionalità, the broader capacity or quality of being rational, and numero razionale, the mathematical notion of a rational number.