Generally, sexual assault falls into one of three categories.
Jennifer Gentile Long, the chief executive officer of AEquitas: The Prosecutors' Resource on Violence Against Women, a global project she co-founded in April 2009, tells SELF those include:
Penetration crimes
Of a body part by another body part (i.e., penal penetration of mouth, anus, vagina)
Of a body part by an object
Contact with genitalia, breast, buttocks, or other intimate body parts
Exposure of genitalia, breast, buttocks or other intimate body parts
https://www.self.com/story/sexual-assault-definition