There are many types of sexual abuse, including:
Non-consensual, forced physical sexual behavior (rape and sexual assault).
Unwanted touching, either of a child or an adult.
Sexual kissing, fondling, exposure of genitalia, and voyeurism, exhibitionism and up to sexual assault.
Exposing a child to pornography.
Saying sexually suggestive statements towards a child (child molestation).
Also applies to non-consensual verbal sexual demands towards an adult.
The use of a position of trust to compel otherwise unwanted sexual activity without physical force (or can lead to attempted rape or sexual assault).
Incest (see also sexual deviancy).
Certain forms of sexual harassment.