zebra
What does zebra mean?
A rare or exotic diagnosis that an over-keen doctor reaches for when the patient almost certainly has the boring common thing. Used as a warning ('stop zebra hunting') and as praise ('she nailed the zebra'). Med students love them; attendings make them rule out the horse first.
Origin
From Dr Theodore Woodward's late-1940s aphorism to his interns at Maryland: 'When you hear hoofbeats, think horses, not zebras.' In Maryland, hoofbeats meant a horse. The Ehlers-Danlos community reclaimed the zebra as their mascot.