adj.
   - lasting for a long time; enduring or continually recurring. 
▸continually engaged in a specified activity:
 a perennial student.
 - (of a plant) living for several years. Compare with annual, biennial.
 - (of a stream or spring) flowing throughout the year.
 
n.
 a perennial plant.
 
  Derivative
  
  Etymology
  C17 (in the sense ‘remaining leafy throughout the year, evergreen’): from L. perennis ‘lasting the year through’ + -ial.