onset

noun

1. a beginning or start: the onset of winter.
2. an assault or attack: an onset of the enemy.
3. Phonetics. the segment of a syllable preceding the nucleus, as the gr in great.Compare coda(def 5), core1(def 14).

noun

1. an attack; assault
2. a start; beginning

n.1530s, “attack, assault,” from on + set (n.); cf. to set (something) on (someone). Weaker sense of “beginning, start” first recorded 1560s. Figurative use in reference to a calamity, disease, etc. is from 1580s. n.

1. A beginning; a start, as of a cold.