Origin and history of widely

"having relatively great extension from side to side; having a certain or specified extension from side to side;" Old English wid, also "vast, long," also used of time; from Proto-Germanic *widaz (source also of Old Saxon, Old Frisian wid, Old Norse viðr, Dutch wijd, Old High German wit, German weit), which is perhaps (Watkins) from PIE *wi-ito-, from root *wi- "apart, away, in half."

The meaning "distended, expanded, spread apart" is attested by c. 1500; the sense of "embracing many subjects" is from 1530s. The meaning "missing the intended target" is from 1580s. Of a dialect, "characterized by a broad accent," by mid-15c.

As a second element in compounds (such as nationwide, worldwide) and meaning "extending through the whole of," it is from late Old English. Wide-screen in reference to cinema projection is by 1931.

common adverbial suffix, forming, from adjectives, adverbs signifying "in a manner denoted by" the adjective; Middle English -li, from Old English -lice, from Proto-Germanic *-liko- (source also of Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko). See -ly (1). It is cognate with lich, and identical with like (adj.).

Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.