Perennial: As in a plant that recurs on a yearly basis in your Zone. A plant can be considered a perennial in a warmer zone, and an annual in a cooler climate. A perennial plant will live 3 years or more.
An herbacious perennial: a plant with non woody stems, will die back in winter and return the next year. Eg. Peonies, Coral Bells
A woody perennial: a plant with woody stems, have buds that stay above ground over winter. E.g. Trees