"A casual date is an evening, a meal, or a get-together of some kind in which there is no expectation of further commitment on either side. Although one side may desire a further relationship, it is understood that both parties are free to sample the company of each other and are as equally free to terminate any sense of relationship as well."
-Daniel Zauber, dailyprincetonian.com

Casual Dating is a loose way of dating. Being able to say Boyfriend Girlfriend yet be able to have sex with as many people as you want.