vestige

1. (by extension) A faint mark or visible sign left by something which is lost, or has perished, or is no longer present.Examples: "the vestiges of ancient magnificence in Palmyra"; "vestiges of former population"; "The result, therefore, of this physical inquiry is, that we find no vestige of a beginning,— no prospect of an end."Synonyms: remainsbroadly

2. (biology) A vestigial organ; a non-functional organ or body part that was once functional in an evolutionary ancestor.Examples: "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."; "This idea was confirmed by Scott, who performed a detailed comparative analysis of primate anatomy and demonstrated conclusively that the appendix is derived for some unidentified function and is not a vestige."

3. (television, radio) The remaining portion of a partially suppressed sideband.Examples: "[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."