Technically, annuals are a large group of plants that complete their life cycle in a single growing season. An annual germinates, flowers, sets seeds and dies with the first frost. In nature, plants grow from these seeds that remain dormant until conditions are right for germination. When light and temperture, mosture and other factors are correct for the particular annual, the life cycle begins all over again.
A few biennials plants needing two seasons to produce flowers and die can be grown to bloom the fist year
A few perennials plants that require two seasons to flower and live year after year can be grown to flower as annuals.