op- / Indo-European roots
Examples of words with the root op-: cooperate, copious, copy, cornucopia, inure, maneuver, manure, officinal, omni-, omnibus, omnium-gatherum, opera, operate, operose, optimum, opulent, opus.
To work, produce in abundance.Oldest form *h3ep-, colored to *h3op-.
▲ Derivatives include opera1, maneuver, manure, opulent, cornucopia.
1. Suffixed form *op-es-. opera1, operate, operose, opus; cooperate, inure, maneuver, manure, officinal, stover from Latin opus (stem oper-), work, with its denominative verb operārī, to work, and secondary noun opera, work.
2. Italic compound *opi-fici-om (see dhē-)
3. Suffixed form *op-en-ent-. opulent from Latin dissimilated opulentus, rich, wealthy.
4. Suffixed form *op-ni-. omni-, omnibus; omnium-gatherum from Latin omnis, all (< "abundant").
5. Suffixed (superlative) form *op-tamo-. optimum from Latin optimus, best (< "wealthiest").
6. copious, copy; cornucopia from Latin cōpia, profusion, plenty, from prefixed form *co-op- (co-, collective and intensive prefix; see kom)
[Pokorny 1. op- 780.]