From WordNet (r) 3.0 (2006) [wn]:
emu
n 1: any of various systems of units for measuring electricity
and magnetism [syn: electromagnetic unit, emu]
2: large Australian flightless bird similar to the ostrich but
smaller [syn: emu, Dromaius novaehollandiae, {Emu
novaehollandiae}]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Emu \E"mu\, n. [Cf. Pg. ema ostrich, F. ['e]mou, ['e]meu, emu.]
(Zo["o]l.)
A large Australian bird, of two species ({Dromaius
Nov[ae]-Hollandi[ae]} and D. irroratus), related to the
cassowary and the ostrich. The emu runs swiftly, but is
unable to fly. [Written also emeu and emew.]
[1913 Webster]
Note: The name is sometimes erroneously applied, by the
Brazilians, to the rhea, or South American ostrich.
[1913 Webster]
Emu wren. See in the Vocabulary.
[1913 Webster]