biennial
Biennial (adjective) means happening once every two years. Example: “The biennial conference returns to Lisbon next spring.”
How to use biennial
Learner’s notesIn plain EnglishSomething that happens every two years.
Neutral. The plant sense is standard gardening vocabulary.
Because biennial and biannual are so easily confused, many writers avoid both and simply say every two years or twice a year.
Trace the full origin ↓Fill the gap
Can you complete this real example?
The _____ conference returns to Lisbon next spring.
Etymology
From Latin biennium, a period of two years, from bi- meaning two and annus meaning year.