1) An elephant on steroids
2) Something that looks like a tusked mammal but is actually modeled after an AT-AT
3) A mumak in the language of the Haradrim
4) An "oiliphant" or an "oliphant" to those who can't spell
5) A wonder of Middle Earth, like Elves, that Sam always wanted to see
6) An opponent that, while bigger than Godzilla's left leg, still "only counts as one!"
"Grey as a mouse, Big as a house, Nose like a snake, I make the earth shake..."
1) Westron (English) name for the Mumak, an elephant or elephant-like monster used in battle by the Haradrim in Lord of the Rings.
2) In Dungeons and Dragons, a larger and more powerful creature similar to an elephant.
The name's just a corruption of "elephant", really.