Onset /(?)/

On·set

Onset

n.
  1. A rushing or setting upon; an attack; an assault; a storming; especially, the assault of an army.
    The onset and retire Of both your armies.
    Who on that day the word of onset gave.
  2. A setting about; a beginning; -- used especially of diseases or pathological symptoms.
    There is surely no greater wisdom than well to time the beginnings and onsets of things.
  3. Anything set on, or added, as an ornament or as a useful appendage. [Obs.]

Onset

v. t.
  1. To assault; to set upon. [Obs.]
  2. To set about; to begin. [Obs.]