Neither of these accusations are correct. Men are sometimes harassed, but most victims of harassment are women. The harasser is almost always male. Examples of sexual harassment include suggestive comments, pressure for sexual contact, demands for sex in return for a job or other benefit, sexual jokes. Sexual assault is an attack of a sexual nature, which includes sexual touching or rape.
Sexual abuse is essentially sexual assault but over a prolonged period of time.
Incest, or sexual relations between family members like parents and children, or brothers and sisters, is an example of sexual abuse. But sexual abuse can occur outside of the immediate family too. Uncles may abuse nieces and nephews. Grandfathers may abuse grandchildren. It is also very important to note that sexual crimes do not necessarily mean that sexual intercourse has taken place.