What does L - R stand for?

Left minus Right [Stereo signals] (NTCM)

Left plus Right [Stereo signals] (NTCM)

Late Run

Launch/Reentry (MCD)

Learning Resources (SAUO)

Left to Right [Ratio] (DAVI)

Life/Revisit [NASA] (KSC)

Local/Remote [Telecommunications] (TEL)

Locus of Radius

Laufend Rechnung [Current Account] [German] [Business term]

Lake and Rail

Landing and Recovery (KSC)

Larceny and Receiving

Left and Right

Loring and Russell's Election Cases in Massachusetts [A publication] (DLA)