or hah


Origin of ha

Middle English word dating back to 1250–1300; see origin at ha-ha1


  1. hectare; hectares.


  1. the sixth letter of the Arabic alphabet, representing a pharyngeal spirant consonant.

Origin of ḥā

From Arabic

  1. the 26th letter of the Arabic alphabet, representing a glottal spirant consonant sound.

Origin of

From Arabic


Symbol, Chemistry, Physics.
  1. hahnium.



or 1H, Ha

Symbol, Chemistry.
  1. protium.


  1. Gunnery. high angle.
  2. in this year.

Origin of h.a.

(def 2) < Latin hōc annō
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for ha

Contemporary Examples of ha

Historical Examples of ha

  • He doesn't want much medicine; that we keep for our enemies,—ha!


    W. A. Fraser

  • "He was to ha' Janet on condeetion that he made the eldership," he fulsomely explained.

  • I daresay your wife'll have a child just about the time you've spent every ha'penny you possess.

    The Foolish Lovers

    St. John G. Ervine

  • The old faellow would not have trusted me if you had not served me at Elmore's—ha!

    Night and Morning, Complete

    Edward Bulwer-Lytton

  • But he'd ha' told anyway, he was so possessed to show that ring.

    Tiverton Tales

    Alice Brown

British Dictionary definitions for ha




  1. an exclamation expressing derision, triumph, surprise, etc, according to the intonation of the speaker
  2. (reiterated) a representation of the sound of laughter


symbol for
  1. hectare


abbreviation for
  1. Hawaii



noun plural h's, H's or Hs
  1. the eighth letter and sixth consonant of the modern English alphabet
  2. a speech sound represented by this letter, in English usually a voiceless glottal fricative, as in hat
    1. something shaped like an H
    2. (in combination)an H-beam


symbol for
  1. physics Planck constant
  2. hecto-
  3. chess See algebraic notation


abbreviation for
  1. hoc anno

Word Origin for h.a.

Latin: in this year


symbol for
  1. chem hydrogen
  2. physics
    1. magnetic field strength
    2. Hamiltonian
  3. electronics henry or henries
  4. thermodynamics enthalpy
  5. (on Brit pencils, signifying degree of hardness of lead) hardH; 2H; 3H Compare B (def. 9)
  6. slang heroin
abbreviation for
  1. Hungary (international car registration)
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

Word Origin and History for ha

c.1300, natural expression of surprise, distress, etc.; found in most European languages; in Old English, Greek, Latin, Old French as ha ha. A ha-ha (1712), from French, was "an obstacle interrupting one's way sharply and disagreeably;" so called because it "surprizes ... and makes one cry Ah! Ah!" [Alexander Le Blond, "The Theory and Practice of Gardening," 1712].


the pronunciation "aitch" was in Old French (ache "name of the letter H"), and is from a presumed Late Latin *accha (cf. Italian effe, elle, emme), with the central sound approximating the value of the letter when it passed from Roman to Germanic, where it at first represented a strong, distinctly aspirated -kh- sound close to that in Scottish loch. In earlier Latin the letter was called ha.

In Romanic languages, the sound became silent in Late Latin and was omitted in Old French and Italian, but it was restored in Middle English spelling in words borrowed from French, and often later in pronunciation, too. Thus Modern English has words ultimately from Latin with missing -h- (e.g. able, from Latin habile); with a silent -h- (e.g. heir, hour); with a formerly silent -h- now often vocalized (e.g. humble, humor, herb); and even a few with an excrescent -h- fitted in confusion to words that never had one (e.g. hostage, hermit).

Relics of the formerly unvoiced -h- persist in pedantic insistence on an historical (object) and in obsolete mine host. The use in digraphs (e.g. -sh-, -th-) goes back to the ancient Greek alphabet, which used it in -ph-, -th-, -kh- until -H- took on the value of a long "e" and the digraphs acquired their own characters. The letter passed into Roman use before this evolution, and thus retained there more of its original Semitic value.

Online Etymology Dictionary, © 2010 Douglas Harper

ha in Medicine


  1. The symbol forPlanck's constant


  1. The symbol for the elementhydrogen
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

ha in Science


  1. Abbreviation of height
  2. The symbol for Planck's constant.


  1. The symbol for henry.
  2. The symbol for hydrogen.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.