Trace

noun

1. An act of tracing.

   "Your cell phone company can put a trace on your line."

2. An enquiry sent out for a missing article, such as a letter or an express package.
3. A mark left as a sign of passage of a person or animal.
4. A residue of some substance or material.

   "There are traces of chocolate around your lips."

5. A very small amount.

   "All of our chocolates may contain traces of nuts."