zebra Noun an African animal, closely related to a horse, with black and white stripes
zebra Noun a referee
zebra Noun an unlikely diagnosis, especially for symptoms probably caused by a common ailment. (Originates in the advice often given to medical students: "When you hear hoof beats, think of horses, not zebras.")
zebra Noun a bi-racial person, specifically one born to a member of the Sub-Saharan African race and a Caucasian.