A chain in which the alternate links are broad blocks connected by thin side links pivoted to the ends of the blocks, used with sprocket wheels to transmit power, as in a bicycle.

plural of block chain

plural of side chain

plural of safety chain

(railways) A normally slack chain for preventing excessive movement between a truck and a car body during a slue.

A form of tackle for loading a log sideways on a sled, skidway, etc.

plural of crotch chain

Synonym of gear case

plural of chain case

(American football) To alter the position of the device, a chain holding two sticks ten yards apart, used to initially determine the position of the line crossing which yields a first down for the offense, which may be moved by penalties or by the offense gaining a first down.