• synonyms


[sem-ee-an-yoo-uh l, sem-ahy-]
  1. occurring, done, or published every half year or twice a year; semiyearly.
  2. lasting for half a year: a semiannual plant.
Show More

Origin of semiannual

First recorded in 1785–95; semi- + annual
Related formssem·i·an·nu·al·ly, adverb
Can be confusedbiannual biennial semiannual (see usage note at bi-1)

Usage note

See bi-1.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for semiannually

Historical Examples of semiannually

  • I am held accountable to the Secretary of the Treasury semiannually for the manner in which the appropriation has been expended.

    Red Men and White

    Owen Wister

  • He had established a branch of his gigantic business there and himself rolled semiannually from coast to coast in his private car.

    Play the Game!

    Ruth Comfort Mitchell

  • Weekly or monthly or yearly, sometimes semiannually, and so forth.

    Warren Commission (8 of 26): Hearings Vol. VIII (of 15)

    The President's Commission on the Assassination of President Kennedy

  • The cockroach is born on the fust ov May and the fust ov November semiannually, and is reddy for use in fifteen days from date.

British Dictionary definitions for semiannually


  1. occurring every half-year
  2. lasting for half a year
Show More
Derived Formssemiannually, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012