onset

The beginning or start of something.

The part of a syllable that precedes the nucleus. In the word nucleus (noo͞′klē-əs), the onset of the first syllable is (n), the onset of the second syllable is (kl), and the last syllable has no onset.

An attack by military forces; an assault.

To assault; begin.

A rushing or setting upon; attack; assault; especially, the assault of an army or body of troops upon an enemy or a fort, or the order for such an assault.