Although legal definitions vary from state to state, sexual assault is a general term for any type of sexual activity that occurs without consent. This could include behavior like unwanted touching or kissing, sexual contact with someone who is under the influence of drugs or alcohol and unable to give an informed "yes" or "no", or rape or attempted rape.
Sexual assault can happen to anyone, regardless of age, gender, race, or sexual orientation.
Every person and experience is different. If you are a survivor of sexual assault, there is support available. The Rape, Abuse, and Incest National Network has a 24-hour hotline that can direct you to local resources – 1-800-656-HOPE. You can also visit other pages on the PACT5 site to learn about what to do if an assault occurs, how to help a friend, and how to be an active bystander.
Consent must be informed (the person being acted upon knows what is happening) and mutual (both parties have input and both want to participate in a given sexual act.)
Communication is important. Consent is not implied; talk to your partner about what is comfortable for him or her every step of the way. Pay attention to both verbal and non-verbal communication - the absence of a "no" does not imply consent, nor does a prior sexual relationship. A person who is mentally or physically incapacitated by drugs or alcohol cannot give consent.
For more on the definition of sexual assault and consent, read SAFER's definition of consent and UC Irvine's page, What is Sexual Assault.
And remember to make the pact and commit to ending sexual violence within your campus community.
95% of campus sexual assaults are unreported. 
90% of women know the person who sexually assaulted or raped them. 
At least 50% of sexual assaults on campus are alcohol-related. 
50% of sexual assaults happened on weekends between midnight and 6AM.