/ˌhɪpəˈpɒtəməs/·noun·1560s CE, in English translations of classical texts describing African fauna; the Latinised form appears in English natural history writing by 1563·Established
Origin
From Greek hippopotamos ('river horse'), combining hippos — from PIE *h₁eḱwos, the same root as Latin equus and English equestrian — with potamos ('river'), the word reached English via Latin in 1563, preserving a 2,500-year-old misidentification by Herodotus who genuinelybelieved the animal was horse-like.
Definition
A large, semi-aquatic African mammal (Hippopotamus amphibius) with a massive barrel-shaped body and broad muzzle, native to sub-Saharan Africa, that spends most of the day submerged in rivers and lakes.
The Full Story
Ancient GreekClassical Greek, 5th century BCEwell-attested
The word 'hippopotamus' is a compound of two Ancient Greek words: 'hippos' (ἵππος), meaning 'horse', and 'potamos' (ποταμός), meaning 'river'. Together they form 'hippopotamos' (ἱπποπόταμος), literally 'riverhorse'. The compound wascoined by the Greeks upon encountering the animal in the Nile region, most likely through contact with ancient Egyptian
Did you know?
Philip — one of the most common names in the ancient and modern world — is etymologically a hippopotamus relative. Both 'hippopotamus' and 'Philip' share the Greekroot hippos ('horse'), which descends from PIE *h₁eḱwos. Philippos meant 'horse-lover,' so every Philip, Felipe, Filippo, and Philippe walking around today carries
the hippopotamus as sacred in the district of Papremis, noting it as four-footed, cloven-hoofed, with a horse's mane and tail, conspicuous tusks, and a horse-like voice. The Greek
Latin 'equus', Sanskrit 'aśva', Old English 'eoh', and Avestan 'aspa'. This PIE root is attested across virtually the entire IE family. The element 'potamos' derives from PIE *peth₂- ('to fly, to rush, to fall'), with the river sense emerging from the notion of rushing or flowing water; cognates include Sanskrit 'patati' ('it flies, falls') and Greek 'pteron' ('wing'). The Latinised form 'hippopotamus' entered scientific and literary Latin during the Republican era, used by writers including Pliny the Elder in his Naturalis Historia (77 CE), who described the animal in detail. English adopted the Latinate form directly. Cognates sharing the 'hippos' root include 'Philip' (from Philippos, 'horse-lover'), 'hippodrome' ('horse-running track'), and 'hippocampus' ('horse-sea-monster', now applied to the brain structure). The plural 'hippopotami' reflects the Latin second-declension form; 'hippopotamuses' is equally correct in English. Key roots: *h₁eḱwos (Proto-Indo-European: "horse (the swift one)"), hippos (ἵππος) (Ancient Greek: "horse"), *peth₂- (Proto-Indo-European: "to rush, to fall, to flow (root of potamos, river)"), potamos (ποταμός) (Ancient Greek: "river").