Definition of by in US English:



  • 1Identifying the agent performing an action.

    by means of, by use of, by virtue of, on account of, as a result of, as a consequence of, owing to, by reason of, on grounds of, on the strength of, due to, thanks to, by, via
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    1. 1.1 After a passive verb.
      ‘the door was opened by my cousin Annie’
      ‘damage caused by fire’
      through the agency of, by means of, under the aegis of, using, utilizing, employing, with the help of, with the aid of, as a result of, because of, by dint of, by way of, by virtue of, via, through
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    2. 1.2 After a noun denoting an action.
      ‘a clear decision by the electorate’
      ‘further attacks by the mob’
    3. 1.3 Identifying the author of a text, idea, or work of art.
      ‘a book by Ernest Hemingway’
  • 2often with verbal noun Indicating the means of achieving something.

    ‘malaria can be controlled by attacking the parasite’
    ‘they plan to provide further working capital by means of borrowing’
    1. 2.1 Indicating a term to which an interpretation is to be assigned.
      ‘what is meant by “fair?”’
    2. 2.2 Indicating a name according to which a person is known.
      ‘she mostly calls me by my last name’
    3. 2.3 Indicating the means of transport selected for a journey.
      ‘traveling by train to Boston’
    4. 2.4 Indicating the other parent of someone's child or children.
      ‘Richard is his son by his third wife’
    5. 2.5 Indicating the sire of a pedigree animal, especially a horse.
      ‘a black filly by Goldfuerst’
    6. 2.6 (followed by a noun without an adjective) in various phrases indicating how something happens.
      ‘I heard by chance that she has married again’
      ‘Anderson, by contrast, rejects this view’
      ‘she ate by candlelight’
  • 3Indicating the amount or size of a margin.

    ‘the shot missed her by miles’
    ‘the raising of taxes by 2.5%’
    1. 3.1 Indicating a unit of measurement.
      ‘billing is by the minute’
    2. 3.2 In phrases indicating something happening repeatedly or progressively, typically with repetition of a unit of time.
      ‘colors changing minute by minute’
      ‘the risk becomes worse by the day’
    3. 3.3 Identifying a parameter.
      ‘a breakdown of employment figures by age and occupation’
    4. 3.4 Expressing multiplication, especially in dimensions.
      ‘a map measuring 24 by 36 inches’
      ‘she multiplied it by 89’
  • 4Indicating a deadline or the end of a particular time period.

    ‘I've got to do this report by Monday’
    ‘by now Kelly needed extensive physiotherapy’
    no later than, in good time for, at, before
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  • 5Indicating location of a physical object beside a place or object.

    ‘remains were discovered by the roadside’
    ‘the lamp was by the door’
    next to, beside, next door to, alongside, at the side of, by the side of, abreast of, adjacent to, cheek by jowl with, side by side with
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    1. 5.1 Past and beyond.
      ‘I drove by our house’
      past, in front of, beyond
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  • 6Indicating the period in which something happens.

    ‘this animal always hunts by night’
  • 7Concerning; according to.

    ‘anything you do is all right by me’
    ‘she had done her duty by him’
    according to, with, as far as … is concerned, concerning
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  • 8Used in mild oaths.

    ‘it was the least he could do, by God’


  • So as to go past.

    ‘a car flashed by on the other side of the road’
    ‘he let only a moment go by’
    past, on, along, beyond
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  • variant spelling of bye


  • by and by

    • Before long; eventually.

      eventually, ultimately, finally, in the end, as time goes by, as time goes on, one day, some day, sooner or later, in time, in a while, after a bit, in the long run, in the fullness of time, at a later time, at a later date, at length, at a future date, at a future time, at some point in the future, in the future, in time to come, in due course
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  • by the by (or bye)

    • Incidentally; parenthetically.

      ‘where's Hector, by the by?’
      less important, of less importance, secondary, subsidiary, subordinate, ancillary, auxiliary
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  • by and large

    • On the whole; everything considered.

      ‘mammals have, by and large, bigger brains than reptiles’
      largely, mostly, mainly, to a large extent, to a great extent, to a great degree, on the whole, chiefly, generally, in general, predominantly, substantially, primarily, overall, for the most part, in the main, principally, in great measure, preponderantly, first and foremost, for all intents and purposes, basically
      on the whole, generally, in general, altogether, all things considered, all in all, taking everything into consideration, for the most part, in the main, as a rule, overall, usually, normally, ordinarily, almost always, customarily, habitually, typically, mainly, mostly, basically, chiefly, predominantly, principally, substantially
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  • by oneself

    • 1Alone.

      ‘living in that big house by himself’
      alone, all alone, on one's own, in a solitary state, singly, separately, solitarily, unaccompanied, companionless, partnerless, unattended, unescorted, unchaperoned, solo
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    • 2Unaided.

      ‘the patient often learns to undress by himself’
      unaided, unassisted, without help, without assistance, by one's own efforts, under one's own steam, independently, single-handed, single-handedly, solo, on one's own, alone, all alone, off one's own bat, on one's own initiative
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Old English bī, bi, be, of Germanic origin; related to Dutch bij and German bei.