h₁eḱwo-drom-
“horse-running place”hippodrome, dromedary
Compound giving Greek hippodromos, English hippodrome, dromedary.
Discussion
The PIE compound *h₁eḱwo-drom- (horse-running place) is a transparent compound of *h₁éḱwos (horse — see the full treatment of the PIE horse word) and *drom- (a running, a course — from *drem- to run). The meaning is "the place where horses run" — a racecourse, a hippodrome.
Greek hippódromos (ἱππόδρομος) continues the compound with the expected Greek treatment of both elements: *h₁éḱwos > híppos (horse) and *drom- > drómos (a running, a racecourse). The hippodrome was one of the most important public venues in the Greek and Byzantine world — the Hippodrome of Constantinople was the social and political centre of the Byzantine Empire for a millennium.
The word hippodrome entered English directly from Greek and remains the technical term for a horse-racing course, particularly in European usage. The combining form -drome (aerodrome, velodrome, palindrome — "running back") became productive in modern English independently of the horse element.
The compound is linguistically significant because it confirms that PIE speakers had compound-word formation rules that could combine an animal name with an activity to produce a place-name — the same grammatical process visible in English compounds like "dog-track" and "swimming-pool." The existence of a dedicated word for a horse-running venue also implies organised equestrian activities in the PIE-speaking world.