omnivorous (adj.)

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."

"omnivorous animal or person," 1890 (as a dictionary word by 1846), formed from omnivorous on model of carnivore/carnivorous. French omnivore was noted as a neologism in that language in 1801 and might be the direct source of the English word.