Why is x an array in the softmax function?

Sorry if this sounds dumb, I'm new to ML. So basically, if the softmax function is "e ^ (x - max(x)) / sum(e^(x - max(x))", I understand what e is, but then what's x? I keep seeing people make x an array, but shouldn't it just be a single number or float? Isn't that what the output would be of the summation formula? Thanks.