zebra.

First attested in 1600. Borrowed from Italian zebra, from Portuguese zebra, zebro (“zebra”), from Old Galician-Portuguese enzebro, ezebra, azebra (“wild ass”), from earlier cebrario (882), ezebrario (897), from Vulgar Latin *eciferus, from Latin equiferus (“wild horse”) (Pliny), from equus (“horse”) + ferus (“wild”). While the word was traditionally pronounced with a long vowel in the first syllable in standard English, during the twentieth century a vowel shift occurred in regions of England, with the shortening of the first vowel. This pronunciation is now used throughout the UK and most Commonwealth nations. The long-vowel pronunciation remains standard in Canadian and American English and is used in the UK only by some older, conservative RP speakers. (unlikely diagnosis): Originates in the advice often given to medical students, "when you hear hoofbeats, think of horses, not zebras". (referee): In reference to the black and white striped shirts they wear.