The Collaborative International Dictionary of English v.0.48:
Jeer \Jeer\, n. [Cf. Gear.] (Naut.) (a) A gear; a tackle. (b) pl. An assemblage or combination of tackles, for hoisting or lowering the lower yards of a ship. [1913 Webster] Jeer capstan (Naut.), an extra capstan usually placed between the foremast and mainmast. [1913 Webster]