An act of tracing. • An enquiry sent out for a missing article, such as a letter or an express package. • A mark left as a sign of passage of a person or animal. • A very small amount, often residual, of some substance or material. • A small amount of rain, not enough to be measured. • A current-carrying conductive pathway on a printed circuit board. • An informal road or prominent path in an arid area. • One of two straps, chains, or ropes of a harness, extending from the collar or breastplate to a whippletree attached to a vehicle or thing to be drawn; a tug. • A connecting bar or rod, pivoted at each end to the end of another piece, for transmitting motion, especially from one plane to another; specifically, such a piece in an organ stop action to transmit motion from the trundle to the lever actuating the stop slider. • The ground plan of a work or works. • The intersection of a plane of projection, or an original plane, with a coordinate plane. • The sum of the diagonal elements of a square matrix. • An empty category occupying a position in the syntactic structure from which something has been moved, used to explain constructions such as wh-movement and the passive. • A sequence of instructions, including branches but not loops, that is executed for some input data. • A signifier approximated in the absence of stable signified.