Words related to *gwa-
Meaning developed through "risk; danger" (a trial of one's chances), c. 1300, and "perilous undertaking" (late 14c.) to "novel or exciting incident, remarkable occurrence in one's life" (1560s). Earlier it also meant "a wonder, a miracle; accounts of marvelous things" (13c.). The -d- was restored in English 15c.-16c.; attempt was made about the same time to restore it in French, but there it was rejected. Venture is a 15c. variant. German Abenteuer is a borrowing of the French word, apparently deformed by influence of Abend "evening."
c. 1600, "a way of approach" (originally a military word), from French avenue "way of access" (16c.), from Old French avenue "act of approaching, arrival," noun use of fem. of avenu, past participle of avenir "to come to, arrive," from Latin advenire "to come to, reach, arrive at," from ad "to" (see ad-) + venire "to come" (from a suffixed form of PIE root *gwa- "to go, come").
The meaning was extended to "a way of approach to a country-house," usually a straight path bordered by trees, hence, "a broad, tree-lined roadway" (1650s), then to "wide, main street" (by 1846, especially in U.S.). By late 19c. in U.S. cities it was used to form the names of streets without reference to character.
"bottom of anything considered as its support, foundation, pedestal," early 14c., from Old French bas "depth" (12c.), from Latin basis "foundation," from Greek basis "a stepping, a step, that on which one steps or stands, pedestal," from bainein "to go, walk, step," from PIE root *gwa- "to go, come."
The military sense "secure ground from which operations proceed" is from 1860. The chemical sense "compound substance which unites with an acid to form a salt" (1810) was introduced in French 1754 by French chemist Guillaume-François Rouelle (1703-1770). Sporting sense of "starting point" is from 1690s, also "destination of a runner" (1812). As a "safe" spot in a tag-like or ball game, suggested from mid-15c. (as the name of the game later called prisoner's base). Hence base-runner (1867), base-hit (1874), etc. Meaning "resources on which something draws for operation" (as in power-base, database, etc.) is by 1959.