part of the brain, from Latin amygdalum "almond" (which the brain parts resemble), from Greek amygdale "almond" (see almond). English had also amygdales "the tonsils" (early 15c.), from a secondary sense of the Latin word in Medieval Latin, a translation of Arabic al-lauzatani "the two tonsils," literally "the two almonds," so called by Arabic physicians for fancied resemblance.
It was altered in Medieval Latin by influence of amandus "loveable." In French it acquired an unetymological -l-, perhaps from Spanish almendra "almond," which got it by influence of the many Spanish words beginning with the Arabic definite article al-. Perhaps through similar confusion, Italian has dropped the first letter entirely (mandorla). As an adjective, applied to eyes shaped like almonds, especially of certain Asiatic peoples, from 1849.