vestige

noun

Etymology: From French vestige, from Latin vestīgium (“footstep, footprint, track, the sole of the foot, a trace, mark”). Doublet of vestigium.

1. A mark left on the earth by a foot.
2. A faint mark or visible sign left by something which is lost, or has perished, or is no longer present.

   “the vestiges of ancient magnificence in Palmyra”

   “vestiges of former population”

3. A vestigial organ; a non-functional organ or body part that was once functional in an evolutionary ancestor.

   “Any person seeing such a condition could not help being frightened at the conditions found, and it seems to me that that fact should lead us to think that the appendix is a vestige or becoming so.”

   “Now this paired organ of Jacobsen began in reptiles and is well developed in many mammals. But in man it is a vestige, often disappearing altogether; and the two openings are closed.”

4. The remaining portion of a partially suppressed sideband.

   “[J]ust a trace, or vestige, of the other sideband is included. In the receiver detection circuitry the vestige of the lower sideband is added to the upper sideband.”