from
The Collaborative International Dictionary of English v.0.48
Foal \Foal\ (f[=o]l), n. [OE. fole, AS. fola; akin to OHG. folo,
G. fohlen, Goth. fula, Icel. foli, Sw. f[*a]le, Gr. pw^los,
L. pullus a young animal. Cf. {Filly}, {Poultry}, {Pullet}.]
(Zo["o].)
The young of any animal of the Horse family {(Equid[ae])}; a
colt; a filly.
[1913 Webster]
{Foal teeth} (Zool.), the first set of teeth of a horse.
{In foal}, {With foal}, being with young; pregnant; -- said
of a mare or she ass.
[1913 Webster]