[1] : The Collaborative International Dictionary of English v.0.48

ally \ally"\, v. t. imp.  p. p. allied; p. pr.  vb. n.
   allying. oe. alien, of. alier, f. alier, fr. l. alligare
   to bind to; ad + ligare to bind. cf. alligate, alloy,
   allay, ligament.
   1. to unite, or form a connection between, as between
      families by marriage, or between princes and states by
      treaty, league, or confederacy; -- often followed by to or
      with.
      1913 webster

            o chief in blood, and now in arms allied. --pope.
      1913 webster

   2. to connect or form a relation between by similitude,
      resemblance, friendship, or love.
      1913 webster

            these three did love each other dearly well,
            and with so firm affection were allied. --spenser.
      1913 webster

            the virtue nearest to our vice allied. --pope.
      1913 webster

   note: ally is generally used in the passive form or
         reflexively.
         1913 webster
see also:
allied allying alligate alloy allay ligament 

Allying >> A Words
Allying, definition of term: Allying
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