also base-board, "line of boarding around the interior walls of a room near the floor," 1854, from base (n.) + board (n.1). Baseboard heating is attested by 1954.

1866, "to confine within set limits," from French interner "send to the interior, confine," from interne "inner, internal" (14c.), from Latin internus "within, internal" (see internal; also compare intern (n.)).

type of rifle or submachine gun, 1968, from Russian Kalashnikov, name of a weapon developed in the Soviet Union c. 1946 and named for Mikhail Kalashnikov, gun designer and part of the team that built it. In AK-47, the AK stands for Avtomat Kalashnikov.

"inmost parts or recesses of a building," especially a temple or shrine, 1660s, from Latin plural of penetral, from penetralis "interior," from the stem of penetrare "to put or get into, enter into" (see penetrate).

"instrument for viewing the interior of the eye," especially the retina, 1857 in English; coined 1852 by German physician and physicist Hermann Ludwig Ferdinand von Helmholtz; see ophthalmo- + -scope.

late 15c., "interior, inward, internal," from Old French intrinsèque "inner" (14c.), from Medieval Latin intrinsecus "interior, internal," from Latin intrinsecus (adv.) "inwardly, on the inside," from intra "within" (see intra-) + secus "along, alongside," from PIE *sekw-os- "following," suffixed form of root *sekw- (1) "to follow."

The form in English was conformed to words in -ic by 18c. Meaning "belonging to the nature of a thing" is from 1640s. Related: Intrinsical; intrinsically.

"the middle; an interior or central part, point, or position," c. 1400, from Middle English middes (mid-14c.), from mid (adj.) + adverbial genitive -s. The unetymological -t is perhaps on model of superlatives (compare against).

"plasterboard, sheetrock; gypsum-based manufactured panel used in interior construction," by 1952, from dry (adj.) + wall (n.). Earlier dry wall meant "a wall built without mortar" (1778).

"antisocial youth," British slang, by 2004, apparently from earlier charver "loutish young person wearing designer-style sportswear," Northern British slang (1997) of uncertain origin. Earlier it was a verb in homosexual slang for "have sex." Perhaps ultimately from Romany (Gypsy).

on the Great Seal of the United States of America, apparently an allusion to line 5 of Virgil's "Eclogue IV," in an 18c. edition: Magnus ab integro seclorum nascitur ordo "The great series of ages begins anew." The seal's designer, Charles Thomson, wrote that the words "signify the beginnings of the New American Era." (see Annuit Coeptis).