Shorthand for a coordinate system in which the position of a point is defined (with some ambiguity) by its distances from two points of known position.Hence, an adjective used to describe a navigation system.

on a jet engine, an exhaust nozzle exit opening which remains constant in area

For jet engines,a maintenance stand designed to provide easy access and alignment for assembly and disassembly.

A method of steering a parachute in a specific direction,initiated by pulling down on the suspension lines.