tracer
UK: ˈtreɪsə | US: ˈtreɪsər
n. a person or thing that traces, especially a device or substance used to track movement or progress
n. a bullet or shell whose flight is made visible by a trail of flames or smoke
n. in computing, a program or tool that records the sequence of operations executed
The word "tracer" originates from the verb "trace," derived from Old French tracer ("to make a line, track"), which in turn comes from Vulgar Latin tractiare ("to drag, draw"). The suffix "-er" is an English agentive suffix, indicating "one who does something." Thus, "tracer" literally means "one who traces" or "a tool for tracing." The term evolved to describe objects like tracer bullets (early 20th century) and later computational tools.
The detective used a tracer to follow the suspect's movements.
Tracer rounds lit up the night sky during the military exercise.
The software includes a network tracer to diagnose connection issues.
Scientists injected a radioactive tracer to study blood flow.
The artist used a light tracer to outline the mural.