From WordNet (r) 2.0 (August 2003) [wn]:
gallinule
n : any of various small aquatic birds of the genus Gallinula
distinguished from rails by a frontal shield and a
resemblance to domestic hens [syn: marsh hen, {water
hen}, swamphen]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Gallinule \Gal"li*nule\, n. [L. gallinula chicken, dim. of
gallina hen: cf. F. gallinule.] (Zool.)
One of several wading birds, having long, webless toes, and a
frontal shield, belonging to the family Rallidae. They are
remarkable for running rapidly over marshes and on floating
plants. The purple gallinule of America is {Ionornis
Martinica}, that of the Old World is Porphyrio porphyrio.
The common European gallinule (Gallinula chloropus) is also
called moor hen, water hen, water rail, moor coot,
night bird, and erroneously dabchick. Closely related to
it is the Florida gallinule (Gallinula galeata).
[1913 Webster]
Note: The purple gallinule of Southern Europe and Asia was
formerly believed to be able to detect and report
adultery, and for that reason, chiefly, it was commonly
domesticated by the ancients.
[1913 Webster]