Since it's been discussed here it might be interesting to hear how top GI's define it
Dr. Regueiro: Most of us define “clinical remission” as a patient who does not require steroids and whose quality of life and physical function is essentially normal. More recently, the term “remission” has evolved to include more objective criteria—specifically mucosal healing—and that has been generally defined by endoscopic or “deep” remission.
this is from this article which discusses whether people can stop taking biologics after they reach remission.
www.gastroendonews.com/ViewArticle.aspx?d=Expert+Roundtable&d_id=233&i=June+2013&i_id=961&a_id=23380Tell me whether you can access this article without a login using this link. Otherwise I don't know how to give access to this article. It is a roundtable discussion by 3 GI's: Reguiro (U of Pittsburgh Medical Ctr), Sandborn (UC San Diego Sch Medicine) and Rubin (Inflammatory Bowel Disease Ctr, U Chicago)
Short answer to whether people can stop biologics after remission: they prefer not stopping but admit that for UC the answer is unclear without studies having more participants. For CD they do not recommend stopping because that disease is progressive.