hart (n.) Look up hart at Dictionary.com
Old English heorot "hart, stag, male deer," from Proto-Germanic *herutaz (cognates: Old Saxon hirot, Old Frisian and Dutch hert "stag, deer," Old High German hiruz, Old Norse hjörtr, German Hirsch "deer, stag, hart"), perhaps from PIE *keru-, extended form of root *ker- (1) "horn" (see horn (n.)). Now, a male deer after its fifth year.