catenary

1. (geometry) The curve described by a flexible chain or a rope if it is supported at each end and is acted upon by no other forces than a uniform gravitational force due to its own weight and variations involving additional and non-uniform forces. It is described by the hyperbolic cosine function.

2. (engineering) Any physical cable, rope, chain, or other weight-supporting structure taking such geometric shape, as a suspension cable for a bridge or a power-transmission line or an arch for a bridge or roof.

3. (nautical) The curve of an anchor cable from the seabed to the vessel; it should be horizontal at the anchor so as to bury the flukes.

4. (transport) A cable, the segments of which between supports take a catenary geometric shape, supporting in turn an overhead conductor that provides trains, trams or trolley buses with electricity, or (metonymic) the combination of the conductor, the cable, and supports.Examples: "The result was catenary being torn down several hundred feet at a time."; "The colour-lights showed up much better than the semaphores which, in spite of their approach warning boards, are not readily visible at any distance between the supports for the catenaries."; "The electric overhead was catenary, using 0000 contact wire, and the new railway employed the latest in electric block signal systems."