The Collaborative International Dictionary of English v.0.48:

Inn \Inn\ ([i^]n), v. i. [imp. & p. p. Inned ([i^]nd); p. pr.
   & vb. n. Inning.]
   To take lodging; to lodge. [R.] --Addison.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Inning \In"ning\, n. [AS. innung, fr. in in, prep. & adv.]
   1. Ingathering; harvesting. [Obs.] --Holland.
      [1913 Webster]

   2. The state or turn of being in; specifically, in cricket,
      baseball, etc., each period during which both teams get
      one turn each at bat; as, in baseball there are nine
      innings to a complete game; -- often in the pl. Hence: The
      turn or time of a person, or a party, in power; as, the
      Whigs went out, and the Democrats had their innings.
      [1913 Webster +PJC]

   3. pl. Lands recovered from the sea. --Ainsworth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

inning
    n 1: (baseball) one of nine divisions of play during which each
         team has a turn at bat [syn: inning, frame]