SLIDING DOOR

The word portcullis was first written down in the influential 1330 verse romance Arthur and Merlin, when it was spelled port colice and had the same definition as today. Other spellings around the time included ​porte colyse, portecule, portculys, portcolyse, and porcules. The earliest attestations hint at the word's origin from the two-word Anglo-Norman phrase porte culiz, which translates to "sliding door". That comes from the Old French words porte, meaning "door", and couleis, meaning "sliding". Porte derives from Latin porta and ultimately the Proto-Indo-European root per, "to pass through". Couleis, meanwhile, probably came from Latin colare, which meant "strain" or "filter". Nobody is sure where that comes from, but we know it's definitely Indo-European because of cognates in Sanskrit.