What do you consider to be "vintage" women's clothing?

I like watching bestdressed and I think I like her style, but sometimes she says something is "vintage". Similarly, Nicole Rafiee sometimes mentions vintage home decor items (not fashion, but still). And I can't identify what is so vintage about these things.

What do you consider to be "vintage" women's clothing? If you're going to say "It depends", then what does it depend on?