onset vs. outset

onset

[ on-set, awn- ]show ipa

noun

1. a beginning or start: the onset of winter.
2. an assault or attack: an onset of the enemy.
3. the segment of a syllable preceding the nucleus, as the gr in great.

outset

[ out-set ]show ipa

noun

1. the beginning or start: I wanted to explain the situation at the outset.
2. outsert.