[rahy-nos-er-uh
s] 
) -os. | 1. | any of several large, thick-skinned, perissodactyl mammals of the family Rhinocerotidae, of Africa and India, having one or two upright horns on the snout: all rhinoceroses are endangered. |
| 2. | Douay Bible. unicorn (def. 4). |
"What is the plural of rhinoceros? ... Well, Liddell and Scott seem to authorize 'rhinocerotes,' which is pedantic, but 'rhinoceroses' is not euphonious." [Sir Charles Eliot, "The East Africa Protectorate," 1905]