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."
ominous
ominously
omission
omit
omittance
omni-
omnibus
omnidirectional
omnifarious
omnipotence
omnipotent