word-forming element meaning "all," from Latin omni-, combining form of omnis "all, every, the whole, of every kind," a word of unknown origin, perhaps literally "abundant," from *op-ni-, from PIE root *op- "to work, produce in abundance."
Entries linking to omni-
*op-
Proto-Indo-European root meaning "to work, produce in abundance."
It forms all or part of: cooperate; cooperation; copious; copy; cornucopia; hors d'oeuvre; inure; maneuver; manure; oeuvre; office; official; officinal; omni-; omnibus; omnium gatherum; op. cit.; opera; operate; operation; operose; optimism; optimum; opulence; opulent; opus; Oscan.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit apas- "work, religious act," apnas- "possession, property;" Hittite happina- "rich;" Avestan huapah- "doing good work, masterly;" Latin opus "a work, labor, exertion;" Greek ompne "food, corn;" Old High German uoben "to start work, to practice, to honor;" German üben "to exercise, practice;" Dutch oefenen, Old Norse æfa, Danish øve "to exercise, practice;" Old English æfnan "to perform, work, do," afol "power."
omnibus n.
1829, "long-bodied, four-wheeled public vehicle with seats for passengers," from French (voiture) omnibus "(carriage) for all, common (conveyance)," from Latin omnibus "for all," dative plural of omnis "all" (see omni-). Introduced by Jacques Lafitte in Paris in 1819 or '20, used in London from 1829.
As an adjective, in reference to legislation, "designed to cover many different cases, embracing numerous distinct objects," recorded from 1835; in U.S., used especially of the Compromise of 1850. Noun meaning "man or boy who assists a waiter at a restaurant" is attested from 1888 (compare busboy).