"act of listening," 1630s, from Latin auscultationem (nominative auscultatio), noun of action from past-participle stem of auscultare "listen attentively to" (see auscultate). Medical sense is from 1821, "a listening to the internal parts of the body via a stethoscope."

"lower part of the alimentary canal," early 15c., from Old French intestin (14c.) or directly from Latin intestinum "a gut," in plural (intestina), "intestines, bowels," noun use of neuter of adjective intestinus "inward, internal," from intus "within, on the inside" (from PIE *entos, suffixed form of root *en "in").

Distinction of large and small intestines in Middle English was made under the terms gross and subtle. Intestine also was used as an adjective in English 16c.-19c. with a sense (as in French) of "internal, domestic, civil."

1839, "gland-like," from medical Latin adenoideus, from Greek adenoeides, from adēn (genitive adēnos) "gland" (from PIE root *engw- "internal organ;" see inguinal) + eidos "form" (see -oid). Adenoids "adenoid growths" is attested by 1856.

1869, originally in chemistry, "causing, relating to, or requiring the absorption of heat," from French endothermique (1868, Berthelot); see endo- + thermal. By 1947 in biology, "dependent on or capable of the internal generation of heat; warm-blooded."

crystalline base, 1885, coined by German physiologist/chemist Albrecht Kossel from Greek adēn "gland," from PIE root *engw- "internal organ" (see inguinal) + chemical suffix -ine (2). So called because it was derived from the pancreas of an ox.

"remove the entrails of, disembowel," c. 1600 (figurative); 1620s (literal), from Latin evisceratus, past participle of eviscerare "to disembowel," from assimilated form of ex "out" (see ex-) + viscera "internal organs" (see viscera). Sometimes used 17c. in a figurative sense of "to bring out the deepest secrets of." Related: Eviscerated; eviscerating.

1919 (implied in kick-starter), "method of starting an internal combustion engine (of a motorcycle) by pushing down a lever with the foot," from kick (n.) + start (n.). Figurative sense of "take a course of action that will quickly start a process" is by 1995.

1832, "any thing which radiates," agent noun in Latin form from radiate (v.). Originally a stove-like apparatus, as a device designed to communicate heat from steam to a room by 1855; the sense of "cooling device in an internal combustion engine" is by 1899.

1510s, "lowest internal part of a ship," also used of the foulness which collects there; variant of bulge "ship's hull," also "leather bag," from Old North French boulge "leather sack," from Late Latin bulga "leather sack," apparently from Gaulish bulga (see bulge (n.)) and compare budget (n.)).