"horseshoe-shaped," 1852, from Latinized form of Greek hippos "horse" (from PIE root *ekwo- "horse.") + krēpis "a boot, half-boot, man's high boot," which is of uncertain origin.
Entries linking to hippocrepian
*ekwo-
Proto-Indo-European root meaning "horse." Perhaps related to *ōku- "swift."
It forms all or part of: alfalfa; Eohippus; equestrian; equine; equus; hippo-; hippocampus; Hippocratic; Hippocrene; hippocrepian; hippodrome; hippogriff; Hippolytus; hippopotamus; Philip; philippic; Philippines; Xanthippe.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit açva-, Avestan aspa-, Greek hippos, Latin equus, Old Irish ech, Old Church Slavonic ehu-, Old English eoh, Gothic aihwa- all meaning "horse."