LP

plural LPs, LP’s.
1.
a phonograph record played at 33 1/3 r.p.m.; long-playing record.
1.
long primer.
2.
low pressure.
noun
1.

2.
long play: a slow-recording facility on a VCR which allows twice the length of material to be recorded on a tape from that of standard play
abbreviation
1.
(in Britain) Lord Provost
2.
Also lp. low pressure

1948, abbreviation of long-playing phonograph record.

The most revolutionary development to hit the recording industry since the invention of the automatic changer is the Long Playing record, which can hold an entire 45-minute symphony or musical-comedy score on a single 12-inch disk. … The disks, released a few weeks ago by Columbia Records and made of Vinylite, have phenomenally narrow grooves (.003 of an inch). They are played at less than half the speed of the standard old-style records. [“Life” magazine, July 26, 1948]

1.
limited partnership
2.
liquid petroleum
3.
liquid propane
4.
long-playing record
5.
Lower Peninsula [of Michigan] lumbar puncture