The New Dictionary of Cultural Literacy, Third Edition. 2002.
ectomorph, endomorph, and mesomorph
(EK-tuh- mawrf) A person whose body structure is dominated by the outer skin and the nervous system. Ectomorphs are thin and have a large skin surface relative to their weight. Endomorphs are heavy and flabby, and mesomorphs are sturdy and strong, with highly developed bones and muscles.