The Collaborative International Dictionary of English v.0.48:
Fern \Fern\ (f[~e]rn), n. [AS. fearn; akin to D. varen, G. farn,
farnkraut; cf. Skr. par[.n]a wing, feather, leaf, sort of
plant, or Lith. papartis fern.] (Bot.)
An order of cryptogamous plants, the Filices, which have
their fructification on the back of the fronds or leaves.
They are usually found in humid soil, sometimes grow
epiphytically on trees, and in tropical climates often attain
a gigantic size.
Note: The plants are asexual, and bear clustered sporangia,
containing minute spores, which germinate and form
prothalli, on which are borne the true organs of
reproduction. The brake or bracken, the maidenhair, and
the polypody are all well known ferns.
Christmas fern. See under Christmas.
Climbing fern (Bot.), a delicate North American fern
(Lygodium palmatum), which climbs several feet high over
bushes, etc., and is much sought for purposes of
Fern owl. (Zool.)
(a) The European goatsucker.
(b) The short-eared owl. [Prov. Eng.] -- Fern shaw, a fern
thicket. [Eng.] --R. Browning.