the word 'taco' entered english as a direct loan from mexican spanish in the early 20th century. in mexican spanish, 'taco' originally referred to a plug, wad, or light lunch, and its use for the food item is believed to derive from the concept of a miner's explosive charge (a 'taco' of gunpowder wrapped in paper), which the rolled food item was thought to resemble. the ultimate origin of the spanish word is uncertain but may come from a nahuatl (aztec language) term 'tlahco', meaning 'half' or 'in the middle', referring to the way the food is folded. the word's journey reflects the cultural transmission of a quintessential mexican food into global cuisine.

this word is a simplex loanword from mexican spanish. it does not contain separable morphemes within its modern english spelling.