It’s two words. This one’s easy.
But of course, a lot of people make the mistake of writing alot instead of a lot. And I’m curious as to why.
I was wondering this recently while reading a book (I can’t remember what one) that used alot… well, a lot. More than a lot in fact; all the time.
Connected speech of course has a large part to play in this. The lack of a gap between the two words makes them sound like one, which makes people assume that alot is actually a single word.
And think about how often you say a lot compared to how often you say the lot. You definitely say a lot… a lot more often. And I think that this means that people are less likely to think of lot as a word on its own, that’s one of two components of the phrase a lot, because a lot isn’t being contrasted with the lot. Or my lot, or which lot or many many other combinations of determiner or noun.
That’s why we don’t write, for example, adog, or ahouse. Because we put lots of determiners before nouns like dog or house: our dog, big house, funny dog, your house, which dog, that house etc. But lot tends to mainly just come after a… a lot.
So much, in fact, that I think most of us don’t think of lot as a noun, but rather think of a lot more like an adverb or an adjective, that’s describing something. So it feels like a single word, with a singular function, and not a combination of an article and a noun. And so people write it as one word.
That’s what I think anyway, and I’ve been thinking about a lot… a lot!