I see router bits marketed as flush trim bits, pattern bits, template bits, but they all seem to be similar in design. The cutting edges are exactly lined up with a bearing, so that an exact copy of a piece can be cut.
For example, Rockler sells a flush trim bit:
and a pattern bit:
and Amazon sells a template bit:
They all seem to be identical in function (although the linked pattern bit is shorter, so it can't cut as deep of a copy as the others can), so is this just a marketing thing? Rockler's flush trim bit I linked is even listed as a "Pattern flush trim bit".