seat stay

Meaning

Noun

• One of the two bicycle frame tubes running diagonally downward from the top of the seat tube to the rear dropouts.

Origin

• (Possibly) borrowed from sailing jargon where "stay" refers to a rope, wire, or rod which runs fore-and-aft along the centerline of a sailing ship from mast to deck, or to another mast, and serves to stabilize the mast.