How do you spell Onset

Available Definitions:
1)  n. - A rushing or setting upon; an attack; an assault; a storming; especially, the assault of an army.
2)  n. - A setting about; a beginning.
3)  n. - Anything set on, or added, as an ornament or as a useful appendage.
4)  v. t. - To assault; to set upon.
5)  v. t. - To set about; to begin.