The Collaborative International Dictionary of English v.0.48:

Watershed \Wa"ter*shed`\, n. [Cf. G. wasserscheide; wasser water
   + scheide a place where two things separate, fr. scheiden to
   separate.]
   [1913 Webster]
   1. The whole region or extent of country which contributes to
      the supply of a river or lake.
      [1913 Webster]

   2. The line of division between two adjacent rivers or lakes
      with respect to the flow of water by natural channels into
      them; the natural boundary of a basin; -- called also
      divide and water parting.
      [1913 Webster +PJC]

   3. a point in time marking an important transition between
      two situations, or phases of an activity; a turning point.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Divide \Di*vide"\, v. t. [imp. & p. p. Divided; p. pr. & vb.
   n. Dividing.] [L. dividere, divisum; di- = dis- + root
   signifying to part; cf. Skr. vyadh to pierce; perh. akin to
   L. vidua widow, and E. widow. Cf. Device, Devise.]
   1. To part asunder (a whole); to sever into two or more parts
      or pieces; to sunder; to separate into parts.
      [1913 Webster]

            Divide the living child in two.       --1 Kings iii.
                                                  25.
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   2. To cause to be separate; to keep apart by a partition, or
      by an imaginary line or limit; as, a wall divides two
      houses; a stream divides the towns.
      [1913 Webster]

            Let it divide the waters from the waters. --Gen. i.
                                                  6.
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   3. To make partition of among a number; to apportion, as
      profits of stock among proprietors; to give in shares; to
      distribute; to mete out; to share.
      [1913 Webster]

            True justice unto people to divide.   --Spenser.
      [1913 Webster]

            Ye shall divide the land by lot.      --Num. xxxiii.
                                                  54.
      [1913 Webster]

   4. To disunite in opinion or interest; to make discordant or
      hostile; to set at variance.
      [1913 Webster]

            If a kingdom be divided against itself, that kingdom
            can not stand.                        --Mark iii.
                                                  24.
      [1913 Webster]

            Every family became now divided within itself.
                                                  --Prescott.
      [1913 Webster]

   5. To separate into two parts, in order to ascertain the
      votes for and against a measure; as, to divide a
      legislative house upon a question.
      [1913 Webster]

   6. (Math.) To subject to arithmetical division.
      [1913 Webster]

   7. (Logic) To separate into species; -- said of a genus or
      generic term.
      [1913 Webster]

   8. (Mech.) To mark divisions on; to graduate; as, to divide a
      sextant.
      [1913 Webster]

   9. (Music) To play or sing in a florid style, or with
      variations. [Obs.] --Spenser.

   Syn: To sever; dissever; sunder; cleave; disjoin; disunite;
        detach; disconnect; part; distribute; share.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Divide \Di*vide"\, v. i.
   1. To be separated; to part; to open; to go asunder.
      --Milton.
      [1913 Webster]

            The Indo-Germanic family divides into three groups.
                                                  --J. Peile.
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   2. To cause separation; to disunite.
      [1913 Webster]

            A gulf, a strait, the sea intervening between
            islands, divide less than the matted forest.
                                                  --Bancroft.
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   3. To break friendship; to fall out. --Shak.
      [1913 Webster]

   4. To have a share; to partake. --Shak.
      [1913 Webster]

   5. To vote, as in the British Parliament, by the members
      separating themselves into two parties (as on opposite
      sides of the hall or in opposite lobbies), that is, the
      ayes dividing from the noes.
      [1913 Webster]

            The emperors sat, voted, and divided with their
            equals.                               --Gibbon.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Divide \Di*vide"\, n.
   A dividing ridge of land between the tributaries of two
   streams; also called watershed and water parting. A
   divide on either side of which the waters drain into two
   different oceans is called a continental divide.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

divide
    n 1: a serious disagreement between two groups of people
         (typically producing tension or hostility)
    2: a ridge of land that separates two adjacent river systems
       [syn: watershed, water parting, divide]
    v 1: separate into parts or portions; "divide the cake into
         three equal parts"; "The British carved up the Ottoman
         Empire after World War I" [syn: divide, split, split
         up, separate, dissever, carve up] [ant: unify,
         unite]
    2: perform a division; "Can you divide 49 by seven?" [syn:
       divide, fraction] [ant: multiply]
    3: act as a barrier between; stand between; "The mountain range
       divides the two countries" [syn: separate, divide]
    4: come apart; "The two pieces that we had glued separated"
       [syn: separate, divide, part]
    5: make a division or separation [syn: separate, divide]
    6: force, take, or pull apart; "He separated the fighting
       children"; "Moses parted the Red Sea" [syn: separate,
       disunite, divide, part]