From The Collaborative International Dictionary of English v.0.48:
Frock \Frock\ (fr[o^]k), n. [F. froc a monk's cowl, coat,
garment, LL. frocus, froccus, flocus, floccus, fr. L. floccus
a flock of wool; hence orig., a flocky cloth or garment; cf.
L. flaccus flabby, E. flaccid.]
1. A loose outer garment; especially, a gown forming a part
of European modern costume for women and children; also, a
coarse shirtlike garment worn by some workmen over their
other clothes; a smock frock; as, a marketman's frock.
[1913 Webster]
2. A coarse gown worn by monks or friars, and supposed to
take the place of all, or nearly all, other garments. It
has a hood which can be drawn over the head at pleasure,
and is girded by a cord.
[1913 Webster]
Frock coat, a body coat for men, usually double-breasted,
the skirts not being in one piece with the body, but sewed
on so as to be somewhat full.
Smock frock. See in the Vocabulary.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Frock \Frock\, v. t.
1. To clothe in a frock.
[1913 Webster]
2. To make a monk of. Cf. Unfrock.
[1913 Webster]