Oh. Then remission is:
dictionary.com said...
Medicine/Medical.
1. a temporary or permanent decrease or subsidence of manifestations of a disease.
2. a period during which such a decrease or subsidence occurs: The patient's leukemia was in remission.
For me, it's a temporary absence of UC symptoms.
I saw this definition a long, long time ago. Somehow I had just assumed everyone else had looked up the definition too.