perennial
adjective /pəˈreniəl/
  /pəˈreniəl/
- continuing for a very long time; happening again and again
- the perennial problem of water shortage
 - that perennial favourite, hamburgers
 - Colonialism in different forms is a perennial theme of history.
 
 - (of plants) living for two years or moreTopics Timec2, Plants and treesc2
 
Word Originmid 17th cent. (in the sense ‘remaining leafy throughout the year, evergreen’): from Latin perennis ‘lasting the year through’ + -ial.