perennialadj/pəˈɹɛn.ɪ.əl/

• 1

  Lasting or remaining active throughout the year, for multiple years, or all the time.

  • a perennial stream
  • [W]hat is most admirable is the vast enclosure, and variety of ground, in yᵉ large garden, containing vineyards, cornefields, meadows, groves (whereof one is of perennial greens), and walkes of vast lengthes, so accurately kept and cultivated, that nothing can be more agreeable.
• 2

  Continuing without cessation or intermission for several years, or for an undetermined or infinite period; never-ending or never failing; perpetual, unceasing.

  • His artwork has a perennial beauty.
  • There, on perennial Adamant deſign'd, / The various Fortunes of your Race you'll find: […]
• 3

  Appearing or recurring again and again; recurrent.

  • a perennial candidate in elections
  • Change is a perennial theme in politics.
• 4

  rareAppearing or recurring again and again; recurrent.

• 5

  biologybotanynatural-sciencesOf a plant: active throughout the year, or having a life cycle of more than two growing seasons.

perennialnoun/pəˈɹɛn.ɪ.əl/

• 1

  biologybotanynatural-sciencesA plant that is active throughout the year, or has a life cycle of more than two growing seasons.

  • One would have supposed from the appearance of the country at the end of the first season after the eruption that practically all plants except the trees and bushes had been destroyed, and that revegetation must be due to new seedlings started on the ash. Such, however, is not the case. Excavation of the root systems of the new plants shows that they are old perennials which have come through the ash from the old soil.
• 2

  A thing that lasts forever.

• 3

  A person or thing (such as a problem) that appears or returns regularly.

  • Some of the stars on our list are perennials who fill huge venues year after year after year, but there's also a returning superstar on our list of the hottest summer tours of 2019.