1. A species of ichneumon (Herpestes nyula). Its fur is beautifully variegated by closely set zigzag markings. O () O, the fifteenth letter of the English alphabet, derives its form, value, and name from the Greek O, through the Latin. The letter came into the Greek from the Ph/nician, which possibly derived it ultimately from the Egyptian. Etymologically, the letter o is most closely related to a, e, and u; as in E. bone, AS. ban; E. stone, AS. stan; E. broke, AS. brecan to break; E. bore, AS. beran to bear; E. dove, AS. d/fe; E. toft, tuft; tone, tune; number, F. nombre.