Worth or costing many millions — of dollars, pounds, or whatever money is being talked about. It is an adjective and it almost never stands alone; it lives glued to another word with a hyphen: a multimillion-dollar contract, a multimillion-pound lawsuit, a multimillion-euro fine. If you drop the money word, the sentence usually sounds unfinished to a native ear. You meet it in news and business writing, where its job is to say 'a very large amount' without giving an exact number — often because the exact number is secret, disputed, or just not the point. That vagueness is deliberate and useful: 'a multimillion-dollar deal' sounds impressive and commits the writer to nothing more precise than 'somewhere above two million'. Notice the number it implies. Multi- means many, so one and a bit million does not qualify; but no one agrees on where the line sits, and writers stretch it freely. Once the figures pass a thousand million, the natural word changes to multibillion. And note the spelling: it is written solid, no hyphen inside the word itself, though the hyphen comes right after when the money word follows.