LP

• left traffic pattern

  ATC

• linear polarization

  ATC

• liquid propane

  General

• localizer performance without vertical guidance

  General

LP has 4 meanings; the right one depends on context. A weather report, a NOTAM or an ATC clearance. Got a NOTAM full of contractions? Paste it into the decoder.

Source: FAA Order JO 7340.2 Contractions. Not for operational use.