<p><strong>Adjective</strong></p><ul><li>agreeable to reason; reasonable; sensible: a rational plan for economic development.</li><li>having or exercising reason, sound judgment, or good sense: a calm and rational negotiator.</li><li>being in or characterized by full possession of one's reason; sane; lucid: The patient appeared perfectly rational.</li><li>endowed with the faculty of reason: rational beings.</li><li>of, relating to, or constituting reasoning powers: the rational faculty.</li><li>proceeding or derived from reason or based on reasoning: a rational explanation.</li><li>capable of being expressed exactly by a ratio of two integers.</li><li>(of a function) capable of being expressed exactly by a ratio of two polynomials.</li><li>capable of measurement in terms of the metrical unit or mora.</li></ul>