A plant, specifically one that people grow in their gardens, which will survive seasonal extremes (usually winter), and therefore not have to be planted again and again. Some will have a dormant stage in which they appear dead. The chrysanthemum is one such well-known flower. Some plants can be considered perinnals in one part of the globe, but will become annuals if moved to colder climes. An annual, on the other hand, only lasts for one growing season.
The Everything Guide to Gardening