9 Grammatical Pitfalls
"bent piece of metal with pointed ends," late 13c., from Old English stapol "post, pillar," from Proto-Germanic *stapulaz "pillar" (cf. Old Frisian stapul "stem of a tooth," Middle Low German stapel "block for executions," German Stapel "stake, beam"), from PIE stebh- (see staff (n.)).
Meaning "piece of thin wire driven through papers to hold them together" is attested from 1895. How this evolved into the modern fastening device is unclear, and it may not be the same word.
"principal article grown or made in a country or district," early 15c., "official market for some class of merchandise," from Anglo-French (14c.), from Old French estaple "market," from a Germanic source akin to Middle Low German stapol, Middle Dutch stapel "market," from the same source as staple (n.1), the notion being of market stalls behind pillars of an arcade, or else of a raised platform where the king's deputies administered judgment. The sense of "principle article grown or made in a place" is 1610s, short for staple ware "wares and goods from a market" (early 15c.).