reference mark

Short definition from Wiktionary

Noun

1. 1
   Used other than figuratively or idiomatically: see reference, mark.
2. 2
   A conventional symbol (such as *, ^, †, or ‡) or number ( ¹ to ᪲ ) in a document , often shown as a superscript, used to refer a reader to a footnote or endnote.