| Noun | 1. | zillion - a very large indefinite number (usually hyperbole); "there were millions of flies" large indefinite amount, large indefinite quantity - an indefinite quantity that is above the average in size or magnitude |
| Adj. | 1. | zillion - very large indeterminate number; "a zillion people were there"cardinal - being or denoting a numerical quantity but not order; "cardinal numbers" |