I. byüˈsefələs noun
( plural bucephaluses -ləsə̇z ; or bucepha·li -ˌlī)
Etymology: after Bucephalus, horse of Alexander the Great died 323B.C. king of Macedon, from Latin, from Greek Boukephalos
archaic : a riding horse especially if spirited and mettlesome — often used ironically
II. noun
Usage: capitalized
Etymology: New Latin, from Greek boukephalos bullheaded — more at bucephala
: a genus of small digenetic trematodes having the mouth near the center of the ventral surface and the intestine saclike and not bifurcated and comprising intestinal parasites of carnivorous fishes