The Collaborative International Dictionary of English v.0.48:

L \L\ ([e^]l), n.
   1. An extension at right angles to the length of a main
      building, giving to the ground plan a form resembling the
      letter L; sometimes less properly applied to a narrower,
      or lower, extension in the direction of the length of the
      main building; a wing. [Written also ell.]
      [1913 Webster]

   2. (Mech.) A short right-angled pipe fitting, used in
      connecting two pipes at right angles. [Written also
      ell.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

L \L\ ([e^]l) n.
   1. L is the twelfth letter of the English alphabet, and a
      vocal consonant. It is usually called a semivowel or
      liquid. Its form and value are from the Greek, through the
      Latin, the form of the Greek letter being from the
      Ph[oe]nician, and the ultimate origin prob. Egyptian.
      Etymologically, it is most closely related to r and u; as
      in pilgrim, peregrine, couch (fr. collocare), aubura (fr.
      LL. alburnus).
      [1913 Webster]

   Note: At the end of monosyllables containing a single vowel,
         it is often doubled, as in fall, full, bell; but not
         after digraphs, as in foul, fool, prowl, growl, foal.
         In English words, the terminating syllable le is
         unaccented, the e is silent, and l is preceded by a
         voice glide, as in able, eagle, pronounced [=a]"b'l,
         [=e]"g'l. See Guide to Pronunciation, [sect]241.
         [1913 Webster]

   2. As a numeral, L stands for fifty in the English, as in the
      Latin language.
      [1913 Webster]

            For 50 the Romans used the Chalcidian chi, ?, which
            assumed the less difficult lapidary type, ?, and was
            then easily assimilated to L.         --I. Taylor
                                                  (The
                                                  Alphabet).
      [1913 Webster]

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):

l
    adj 1: being ten more than forty [syn: fifty, 50, l]
    n 1: a metric unit of capacity, formerly defined as the volume
         of one kilogram of pure water under standard conditions;
         now equal to 1,000 cubic centimeters (or approximately 1.75
         pints) [syn: liter, litre, l, cubic decimeter,
         cubic decimetre]
    2: the cardinal number that is the product of ten and five [syn:
       fifty, 50, L]
    3: a cgs unit of illumination equal to the brightness of a
       perfectly diffusing surface that emits or reflects one lumen
       per square centimeter [syn: lambert, L]
    4: the 12th letter of the Roman alphabet [syn: L, l]