What is the meaning of Onset?

The initial phase of a disease or condition, in which symptoms first become apparent.

The initial portion of a syllable, preceding the syllable nucleus.

The beginning of a musical note or other sound, in which the amplitude rises from zero to an initial peak.

A setting about; a beginning.

Anything added, such as an ornament or as a useful appendage.

An attack; an assault especially of an army.

To assault; to set upon.

To set about; to begin.

bear cub, bearlet

Source: wiktionary.org