The Collaborative International Dictionary of English v.0.48:

Alley \Al"ley\, n.; pl. Alleys. [A contraction of alabaster,
   of which it was originally made.]
   A choice taw or marble. --Dickens.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Alley \Al"ley\, n.; pl. Alleys. [OE. aley, alley, OF. al['e]e,
   F. all['e]e, a going, passage, fr. OE. aler, F. aller, to go;
   of uncertain origin: cf. Prov. anar, It. andare, Sp. andar.]
   1. A narrow passage; especially a walk or passage in a garden
      or park, bordered by rows of trees or bushes; a bordered
      way.
      [1913 Webster]

            I know each lane and every alley green. --Milton.
      [1913 Webster]

   2. A narrow passage or way in a city, as distinct from a
      public street. --Gay.
      [1913 Webster]

   3. A passageway between rows of pews in a church.
      [1913 Webster]

   4. (Persp.) Any passage having the entrance represented as
      wider than the exit, so as to give the appearance of
      length.
      [1913 Webster]

   5. The space between two rows of compositors' stands in a
      printing office.
      [1913 Webster]

WordNet (r) 3.0 (2006):

alley
    n 1: a narrow street with walls on both sides [syn: alley,
         alleyway, back street]
    2: a lane down which a bowling ball is rolled toward pins [syn:
       bowling alley, alley, skittle alley]