Definitions for "Form criticism"
The study of biblical texts by looking at the literary genres that form their backgrounds and contexts and usually relate to the historical circumstances as well.
An assessment of how particular, set literary structures (e.g. a hymn) function and the type of social setting where such literary forms would have originated in an effort better to perceive their intent.
as applied esp. to the Bible, the attempt to trace the provenance and assess the historicity of particular passages by a close analysis of their structural forms. The success of the method depends largely on the assumption that the same forms recur in nonbiblical literature (Cross, The Oxford Dictionary Of The Christian Church).
the process of categorizing a pericope according to its structure and its original life setting. See this site for some examples of NT forms