one \one\, n.
   1. a single unit; as, one is the base of all numbers.
      1913 webster

   2. a symbol representing a unit, as 1, or i.
      1913 webster

   3. a single person or thing. "the shining ones." --bunyan.
      "hence, with your little ones." --shak.
      1913 webster

            he will hate the one, and love the other. --matt.
                                                  vi. 24.
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            that we may sit, one on thy right hand, and the
            other on thy left hand, in thy glory. --mark x. 37.
      1913 webster

   after one, after one fashion; alike. obs. --chaucer.

   at one, in agreement or concord. see at one, in the
      vocab.

   ever in one, continually; perpetually; always. obs.
      --chaucer.

   in one, in union; in a single whole.

   one and one, one by one, singly; one at a time; one after
      another. "raising one by one the suppliant crew."
      --dryden.

   one on one contesting an opponent individually; -- in a
      contest.

   go one on one, to contest one opponent by oneself; -- in a
      game, esp. basketball.
      1913 webster +pjc
see also:
after one at one ever in one in one one and one one by one 
one on one go one on one 

by \by\ bimac, prep. oe. bi, as. bimac, big, near to, by,
   of, from, after, according to; akin to os.  ofries. bi, be,
   d. bij, ohg. bimac, g. bei, goth. bi, and perh. gr. 'amfi`.
   e. prefix be- is orig. the same word. root203. see pref.
   be-.
   1. in the neighborhood of; near or next to; not far from;
      close to; along with; as, come and sit by me.
      1913 webster

            by foundation or by shady rivulet
            he sought them both.                  --milton.
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   2. on; along; in traversing. compare 5.
      1913 webster

            long labors both by sea and land he bore. --dryden.
      1913 webster

            by land, by water, they renew the charge. --pope.
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   3. near to, while passing; hence, from one to the other side
      of; past; as, to go by a church.
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   4. used in specifying adjacent dimensions; as, a cabin twenty
      feet by forty.
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   5. against. obs. --tyndale 1. cor. iv. 4.
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   6. with, as means, way, process, etc.; through means of; with
      aid of; through; through the act or agency of; as, a city
      is destroyed by fire; profit is made by commerce; to take
      by force.
      1913 webster

   note: to the meaning of by, as denoting means or agency,
         belong, more or less closely, most of the following
         uses of the word:
      a it points out the author and producer; as, "waverley",
          a novel by sir w.scott; a statue by canova; a sonata
          by beethoven.
      b in an oath or adjuration, it indicates the being or
          thing appealed to as sanction; as, i affirm to you by
          all that is sacred; he swears by his faith as a
          christian; no, by heaven.
      c according to; by direction, authority, or example of;
          after; -- in such phrases as, it appears by his
          account; ten o'clock by my watch; to live by rule; a
          model to build by.
      d at the rate of; according to the ratio or proportion
          of; in the measure or quantity of; as, to sell cloth
          by the yard, milk by the quart, eggs by the dozen,
          meat by the pound; to board by the year.
      e in comparison, it denotes the measure of excess or
          deficiency; when anything is increased or diminished,
          it indicates the measure of increase or diminution;
          as, larger by a half; older by five years; to lessen
          by a third.
      f it expresses continuance or duration; during the
          course of; within the period of; as, by day, by night.
      g as soon as; not later than; near or at; -- used in
          expressions of time; as, by this time the sun had
          risen; he will be here by two o'clock.
          1913 webster

   note: in boxing the compass, by indicates a pint nearer to,
         or towards, the next cardinal point; as, north by east,
         i.e., a point towards the east from the north;
         northeast by east, i.e., on point nearer the east than
         northeast is.
         1913 webster

   note: with is used instead of by before the instrument with
         which anything is done; as, to beat one with a stick;
         the board was fastened by the carpenter with nails. but
         there are many words which may be regarded as means or
         processes, or, figuratively, as instruments; and
         whether with or by shall be used with them is a matter
         of arbitrary, and often, of unsettled usage; as, to a
         reduce a town by famine; to consume stubble with fire;
         he gained his purpose by flattery; he entertained them
         with a story; he distressed us with or by a recital of
         his sufferings. see with.
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   by all means, most assuredly; without fail; certainly.

   by and by.
      a close together of place. obs. "two yonge knightes
          liggyng lying by and by." --chaucer.
      b immediately; at once. obs. "when . . . persecution
          ariseth because of the word, by and by he is
          offended." --matt. xiii. 21.
      c presently; pretty soon; before long.

   note: in this phrase, by seems to be used in the sense of
         nearness in time, and to be repeated for the sake of
         emphasis, and thus to be equivalent to "soon, and
         soon," that is instantly; hence, -- less emphatically,
         -- pretty soon, presently.

   by one's self, with only one's self near; alone; solitary.

   by the bye. see under bye.

   by the head naut., having the bows lower than the stern;
      -- said of a vessel when her head is lower in the water
      than her stern. if her stern is lower, she is by the
      stern.

   by the lee, the situation of a vessel, going free, when she
      has fallen off so much as to bring the wind round her
      stern, and to take her sails aback on the other side.

   by the run, to let go by the run, to let go altogether,
      instead of slacking off.

   by the way, by the bye; -- used to introduce an incidental
      or secondary remark or subject. 

   day by day, one by one, piece by piece, etc., each day,
      each one, each piece, etc., by itself singly or
      separately; each severally.

   to come by, to get possession of; to obtain.

   to do by, to treat, to behave toward.

   to set by, to value, to esteem.

   to stand by, to aid, to support.
      1913 webster

   note: the common phrase good-by is equivalent to farewell,
         and would be better written good-bye, as it is a
         corruption of god be with you b'w'ye.
         1913 webster
see also:
be- with by all means by and by by one's self by the bye 
bye by the head by the lee by the run by the way 
day by day one by one piece by piece to come by to do by 
to set by to stand by 

one by one
     adv 1: in single file; "the prisoners came out one by one" syn: one
            after another, one at a time
     2: one piece at a time; "she sold the plates by the piece"
        syn: by the piece
     3: apart from others; "taken individually, the rooms were, in
        fact, square"; "the fine points are treated singly" syn:
        individually, separately, singly, severally, on
        an individual basis
see also:
one after another one at a time by the piece individually separately singly 
severally on an individual basis 

29 moby thesaurus words for "one by one":
   adrift, alone, apart, apart from, apiece, aside from, asunder,
   away from, by itself, each, each to each, in the abstract,
   in the singular, in twain, in two, independently, individually,
   once, particularly, per annum, per capita, per se, piecemeal,
   respectively, separately, severally, single-handedly, singly,
   singularly