"Rhinoceros" is a Greek word, but what does it mean?

Rhinoceros is Greek (ρινόκερος), and means "nose-horn", from Greek ρις (rhis, "nose" and κερος (keros, "horn"). The plural in English is rhinoceros or rhinoceroses. The collective noun for a group of rhinoceroses is crash or herd. The name has been in use since the 14th century.

Rhinoceroses are encountered in Africa, Northern India, Indochina and Indonesia. The family Rhinocerotidae consists of only four extant genera: Ceratotherium (white rhinoceros), Diceros (black rhinoceros), Dicerorhinus (Sumatran rhinoceros), and Rhinoceros (Indian and Javan rhinoceros). The living species fall into three categories.

The two African species, the white rhinoceros and the black rhinoceros, belong to the tribe Dicerotini, which originated in the middle Miocene, about 14.2 million years ago. The species diverged during the early Pliocene (about 5 million years ago). There are two living Rhinocerotini species, the Indian rhinoceros and the Javan rhinoceros, which diverged from one another about 10 million years ago. The Sumatran rhinoceros is the only surviving representative of the most primitive group, the Dicerorhinini, which emerged in the Miocene (about 20 million years ago).

In many European languages, the name "rhinoceros" is calqued, such as German "Nashorn", Swedish "noshörning" and Finnish "sarvikuono".

Of the other options, "hippopotamus" means "river horse" and "monokeros" means "one-horned", which is "unicornus" in Latin.