Noun
a clef that puts the F below middle C on the fourth line of a staff
Source: WordNetThe F clef notated to sound an octave lower is used for contrabass instruments such as the double bass and contrabassoon. Source: Internet
It is precisely the equivalent to the other more common form of the baritone clef, an F clef placed on the 3rd line (see above ). Source: Internet
The ethnomusicologists were the only ones to note some traditional airs in the normal grand staff method using the G clef and the F clef. Source: Internet
The F clef can also be notated with an octave marker. Source: Internet