lp(n = noun.artifact) l-p - a long-playing phonograph record; designed to be played at 33.3 rpm;
is a kind of disc, disk, phonograph record, phonograph recording, platter, record

   a long-playing phonograph record; designed to be played at 33.3 rpm. [WordNet 1.5]

lp, abbr.
1 long-playing (gramophone record).
2 low pressure.