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

back-to-back \back-to-back\ adj.
   1. occurring immediately one after the other; consecutive.
      back-to-back home runs

   syn: consecutive.
        wordnet 1.5

   2. oriented with the backs toward each other, and sometimes
      touching.
      wordnet 1.5

[2] : WordNet (r) 2.0

back-to-back
     adj : one after the other; "back-to-back home runs" syn: consecutive
see also:
consecutive 

Back-To-Back >> B Words
Back-To-Back, definition of term: Back-To-Back
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