mid-14c., "net to catch fish" (implied in trammeller "one who fishes with a trammel net"), from Old French tramail "fine-gauged fishnet" (13c.), from Late Latin tremaculum, perhaps meaning "a net made from three layers of meshes," from Latin tri- "three" (see tri-) + macula "a mesh" (see mail (n.2)). Meaning "anything that hinders" is from 1650s, originally "a hobble for a horse" (c. 1500). 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.), a figurative use from the literal sense "bind (a horse's legs) with a trammel" (c. 1600). Related: Trammeled; trammeling.
early 13c., past tense and alternative past participle of hide (v.1).
How to entangle, trammel up and snare
Your soul in mine, and labyrinth you there
Like the hid scent in an unbudded rose?
Aye, a sweet kiss — you see your mighty woes.
[Keats, from "Lamia," 1820]