[trac.er] n (ca. 1552) 1: one that traces, tracks down, or searches out: as a: a person who traces missing persons or property and esp. goods lost in transit b: an inquiry sent out in tracing a shipment lost in transit
2: one who traces designs, patterns, or markings
3: a device (as a stylus) used in tracing
4. a: ammunition containing a chemical composition to mark the flight of projectiles by a trail of smoke or fire b: a substance used to trace the course of a chemical or biological process; esp: label 3d