The Collaborative International Dictionary of English v.0.48:

L \L\, a.
   1. Having the general shape of the (capital) letter L; as, an
      L beam, or L-beam.
      [Webster 1913 Suppl.]

   2. Elevated; -- a symbol for el. as an abbreviation of
      elevated in elevated road or railroad. -- n. An elevated
      road; as, to ride on the L. [Colloq., U. S.]
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

EL
    n 1: angular distance above the horizon (especially of a
         celestial object) [syn: elevation, EL, altitude,
         ALT]
    2: a railway that is powered by electricity and that runs on a
       track that is raised above the street level [syn: elevated
       railway, elevated railroad, elevated, el, overhead
       railway]