This is generally differentiated from a one-hit wonder in that the artist usually has had success with other songs as well.
A signature song may be a song that spearheads an artist's initial mainstream breakthrough, a song that revitalizes an artist's career, or a song that simply represents a high point in an artist's career.
Often, a signature song will feature significant characteristics of an artist and may encapsulate the artist's particular sound and style.
Signature songs can be the result of spontaneous public identification, or a marketing tool developed by the music industry to promote artists, sell their recordings, and develop a fan base.
[1] Artists and bands with a signature song are generally expected to perform it at every concert appearance, often as an encore on concert tours, sometimes being the last song of the setlist.