Perennial = comes back every year. The upper part of the plant will die at the end of the season , but will return the next spring. Depending on the type of perennials:some can last for three years.
Annual = Grows, blooms and dies in a single year. Annuals are used to provide season long color in borders and containers.
Biennial = Grows from seed in one year and flowers in the next. The first year it provides foliage . it dies at the second year but many are self seeding so a new crop will grow the next year.
Source: Ontario Gardener