The "soul patch"

[Grant Barrett]

Another term for it is "flavor saver," presumably due to the food
that gets caught in it. There's a 1986 hit on Google Groups where the
term refers to a beard and mustache together.

http://groups-beta.google.com/group/soc.singles/msg/ba9c977e8b17d14c

The next hit there where it specifically refers to the tuft of hair
beneaht the lower lip (which is what I know it as) is 1996.

http://groups-beta.google.com/group/rec.music.gdead/msg/722ff50238401211

Grant Barrett
gbarrett at worldnewyork.org