Answer:
No. Colitis is inflammation of the colon (often used to describe inflammation of the whole large intestine - colon, rectum and cecum), which can be caused by a variety of things - for example Crohn's disease, infection or chemicals from an enema.
Ulcerative colitis is more specific - it is a form of colitis, characterised by ulcers (open sores) in the colon. However, people who suffer from ulcerative colitis may just say "colitis" - although more commonly it is abbreviated to UC.