biennial

/baɪˈɛniəl/

/baɪˈɛniəl/

Other forms: biennials

If you’re just as fanatical about the luge as you are about beach volleyball, you probably know that the Olympic Games are on a biennial schedule. Every two years, either the Summer or the Winter Olympics takes place.

Don't mistake biennial for biannual, which means “twice a year.” Annoying? Yes, but other words containing the prefix bi- are even more troublesome. For example, bimonthly can mean either “twice a month” or “every two months.” To avoid confusion, you can use the prefix semi- to mean “twice during a certain time period.” So, it’s correct to say that the Olympics occurs on a biennial schedule, not on a semiannual (or biannual) one.

Definitions of biennial

1. adjective

   occurring every second year
   “they met at biennial conventions”

   synonyms: biyearly

   periodic, periodical

   happening or recurring at regular intervals
2. noun

   (botany) a plant having a life cycle that normally takes two seasons from germination to death to complete; flowering biennials usually bloom and fruit in the second season
   type of:

   flora, plant, plant life

   (botany) a living organism lacking the power of locomotion
3. adjective

   having a life cycle lasting two seasons
   “a biennial life cycle”

   “parsnips and carrots are biennial plants often grown as annuals”

   synonyms: two-year

   antonyms:

   annual

   completing its life cycle within a year

   perennial

   lasting three seasons or more