Fair question: As to the definition of this common medical term, with regards to UC what could generally be considered to be 'in a state of remission'?
Whilst on a 'maintenance' drug eg Azathiprine say 50-150g per day to negate any inevitable relapse.
1) completely 'normal' ie 1 BM per day (even 0 occasionally) no urgency, no bleeding or D, well-formed stool, eat whatever you want etc. (within reason)
2) 'almost normal' ie 2 BM's per day, no urgency, no bleeding or D, stool fairly firm but ocassionally 'ribboned'. No pain etc.
3) 3 to 4 BM's, slight urgency, only sporadic minor bleeding, some firm but mainly sloppy stool, occasional rectal pain etc.
4) 4 to 6 BM's, regular but only minor bleeding, urgency, occasional tenesmos, some D, having to take pain killers and rectal meds etc.
5) 6 to 10 BM's ( afternoons and nights as well) heavier bleeding/pain/urgency/tenesmos/D/ moaning in the bathroom and contemplating suicide etc. 
You might want to disregard #5 as it would probably constitute a 'flare-up' and prompt a rapid return to Prednisone and calling your GI.
I realise everyone probably has a different take on what they would call 'remission' but you can be sure I'm not the only one that's curious.
FYI, I'm at about #2 with occasional days at #3.