Side somi is the one and only context in which it is acceptable to abbreviate somersault as “somi,” and even then only because of irreversible convention. Otherwise, no.
The side somi may be the most famous of all the aggressively hideous beam skills—a serious competition—notable because the very idea of flipping sideways in an aggressive cowboy position is flattering on no human being ever born. I mean, look at the skill drawing. Even the drawing looks like the “don’t be like this” safety picture on the back of a ladder.