Origin and history of engulf

late 14c., "profound depth," from Old French golf "a gulf, whirlpool," from Italian golfo "a gulf, a bay," from Late Latin colfos, from Greek kolpos "bay, gulf of the sea," earlier "trough between waves, fold of a loose garment," originally "bosom," the common notion being "curved shape."

This is from PIE *kuolp- "arch, curve, vault" (compare Old English hwealf "vault," a-hwielfan "to overwhelm," Old Norse holfinn "vaulted," Old High German welban "to vault").

The geographic sense "large tract of water extending into the land" (larger than a bay, smaller than a sea, but the distinction is not exact and not always observed) is in English from c. 1400, replacing Old English sæ-earm. The figurative sense of "a wide interval" is from 1550s.

Latin sinus underwent the same development, being used first for "bosom," later for "gulf" (and in Medieval Latin, "hollow curve or cavity in the body"). Blount (1656) defines English gulph as "a part the Sea, insinuating and embosoming it self within the land, or between two several lands."

The U.S. Gulf States have been so called from 1836. The Gulf Stream (1775) takes its name from the Gulf of Mexico.

word-forming element meaning "in; into," from French and Old French en-, from Latin in- "in, into" (from PIE root *en "in"). Typically assimilated before -p-, -b-, -m-, -l-, and -r-. Latin in- became en- in French, Spanish, Portuguese, but remained in- in Italian.

Also used with native and imported elements to form verbs from nouns and adjectives, with a sense "put in or on" (encircle), also "cause to be, make into" (endear), and used as an intensive (enclose). Spelling variants in French that were brought over into Middle English account for parallels such as ensure/insure, and most en- words in English had at one time or another a variant in in-, and vice versa.