Overview
Sexual assault is an act in which one intentionally sexually touches another person without that person's consent, or coerces or physically forces a person to engage in a sexual act against their will. It is a form of sexual violence that includes child sexual abuse, groping, rape (forced sexual penetration, no matter how slight), drug facilitated sexual assault, and the torture of the person in a sexual manner.
Definition
Generally, sexual assault is defined as unwanted sexual contact. The National Center for Victims of Crime states:
In the United States, the definition of sexual assault varies widely among the individual states. However, in most states sexual assault occurs when there is lack of consent from one of the individuals involved. Consent must take place between two adults who are not incapacitated and consent may change, by being withdrawn, at any time during the sexual act.
Types
From Wikipedia (CC BY-SA 4.0).