I have a pot with mint plants growing in it. These plants die off in the winter and resurface from the ground in spring each year. Does that make the mint plants perennial? If not, is there a special term for these types of plants instead?
Yes mint plants are perennials. Actually all plants that live longer than 2 years are considered perennials. Plants that only live one or two years are called annuals or biennials, respectively.
Small plants, like mint, that grow back from their rootstock are sometimes more specifically also called herbaceous perennials.