From on- +‎ set. Compare Old English onsettan (to impose; oppress, bear down).



onset (plural onsets)

  1. (archaic) A rushing or setting upon; an attack; an assault; a storming; especially, the assault of an army.
    • c. 1596, William Shakespeare, “The Life and Death of King Iohn”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358, [Act II, scene i]:
      Heralds, from off our towers, we might behold
      From first to last, the onset and retire
      Of both your armies
    • (Can we date this quote by William Wordsworth and provide title, author's full name, and other details?),
      Who on that day the word of onset gave.
  2. (medicine) The initial phase of a disease or condition, in which symptoms first become apparent.
    the onset of schizophrenia
  3. (phonology) The initial portion of a syllable, preceding the syllable nucleus.
    Antonym: coda
    Coordinate terms: nucleus, coda
    Holonym: syllable
  4. (acoustics) The beginning of a musical note or other sound, in which the amplitude rises from zero to an initial peak.
  5. A setting about; a beginning.
    Synonyms: start, beginning; see also Thesaurus:beginning
    the onset of puberty
    • (Can we date this quote by Francis Bacon and provide title, author's full name, and other details?),
      There is surely no greater wisdom than well to time the beginnings and onsets of things.
    • 2013 June 29, “High and wet”, in The Economist, volume 407, number 8842, page 28:
      Floods in northern India, mostly in the small state of Uttarakhand, have wrought disaster on an enormous scale. The early, intense onset of the monsoon on June 14th swelled rivers, washing away roads, bridges, hotels and even whole villages. Rock-filled torrents smashed vehicles and homes, burying victims under rubble and sludge.
  6. (obsolete) Anything set on, or added, as an ornament or as a useful appendage.
    • 1592, William Shakespeare , Titus Andronicus, Act 1, Scene 1
      And will with deeds requite thy gentleness:
      And, for an onset, Titus, to advance
      Thy name and honourable family,
      Lavinia will I make my empress.
    (Can we find and add a quotation of Johnson to this entry?)



onset (third-person singular simple present onsets, present participle onsetting, simple past and past participle onset)

  1. (obsolete) To assault; to set upon.
  2. (obsolete) To set about; to begin.