Entry 3 senses · 3 variants Webster, 1913 Mental /mĕn'-təl/ · Men·tal · IPA /ˈmɛn.təl/ a. n. a. 01 a. Of or pertaining to the chin; genian; as, the mental nerve; the mental region. 1. Of or pertaining to the chin; genian; as, the mental nerve; the mental region.(Anat.) 02 n. A plate or scale covering the mentum or chin of a fish or reptile. 1. A plate or scale covering the mentum or chin of a fish or reptile.(Zool.) 03 a. Of or pertaining to the mind; intellectual; as, mental faculties; mental operations, conditions, or exercise. 1. Of or pertaining to the mind; intellectual; as, mental faculties; mental operations, conditions, or exercise. “What a mental power This eye shoots forth!” — Shak. Phrases & compounds Mental alienation — insanity. Mental arithmetic — the art or practice of solving arithmetical problems by mental processes, unassisted by written figures.