mid-14c. (implied in trammeller) "net to catch fish," from Middle French tramail, from Old French (early 13c.), from Late Latin tremaculum, perhaps meaning "a net made from three layers of meshes," from Latin tri- "three" + macula "a mesh" (see mail (2)). Italian tramaglio, Spanish trasmallo are French loan-words.
1530s, originally "to bind up (a corpse);" sense of "hinder, restrain" is from 1727, from trammel (n.). Related: Trammeled; trammeling.