[ sem-ee-an-yoo-uh l, sem-ahy- ]
/ ˌsɛm iˈæn yu əl, ˌsɛm aɪ- /


occurring, done, or published every half year or twice a year; semiyearly.
lasting for half a year: a semiannual plant.

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. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for semiannually

  • 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.

  • 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
  • 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
  • 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

British Dictionary definitions for semiannually


/ (ˌsɛmɪˈænjʊəl) /


occurring every half-year
lasting for half a year
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