What is the meaning of Stim?

Sensory stimulation.

Any repetitive self-stimulatory behavior (e.g. hand flapping, head banging, repeating noises or words), frequent in autistic people.

To perform such a repetitive self-stimulatory action.

Synonym of stimulant (drug).

A whit or jot; the least amount.

a school or shoal (group of fish)

a school or shoal (group of fish)

a school (a group of fish)

bustle, buzz ((excited activity with) loud noise of many blended voices)

voice

vote

Source: wiktionary.org