LINE UP [AND WAIT] (ICAO) - Clearance to enter runway and await
take-off clearance.
(Source: Doc 4444-ICAO Air Traffic Management)
Example: LINE UP [AND WAIT]; LINE UP RUNWAY (number); LINE
UP. BE READY FOR IMMEDIATE DEPARTURE; or.........................
conditional clearances LINE UP. Response: (condition) LINING UP

LOCAL AIRPORT ADVISORY (LAA) (P/CG) - A service provided by
flight service stations or the military at airports not serviced by an
operating control tower. This service consists of providing
information to arriving and departing aircraft concerning wind
direction and speed, favored runway, altimeter setting, pertinent
known traffic, pertinent known field conditions, airport taxi routes
and traffic patterns, and authorized instrument approach
procedures. This information is advisory in nature and does not
constitute an ATC clearance.

LOCALIZER (P/CG) - The component of an Instrument Landing
System which provides course guidance to the runway. (See
Instrument Landing System)

LOCALIZER (JCS, NATO) - A directional radio beacon which
provides to an aircraft an indication of its lateral position relative
to a predetermined final approach course. (See Instrument
Landing System)

LOCALIZER COURSE (INSTRUMENT LANDING SYSTEM) (ICAO) - The locus of points, in any given horizontal plane, at which the DDM (difference in depth of modulation) is zero.
LOCALIZER (ICAO) - PANS-OPS abbreviates the localizer facility as LLZ. The accuracy of the signal generated by the LLZ is the same as a LOC. PANS-OPS requires the LLZ final approach track alignment to remain within 5° of the  runway centerline. If the alignment exceeds 5°, PANS-OPS allows an increase of the final approach track to 15° for categories C, D, and E. For aircraft categories A and B, the maximum angle formed by the final approach track and the runway centerline is 30°.
NOTE - Prior to flying a LDA or LLZ, compare the final approach course with the runway heading. The airport sketch should provide a visual indication of the angle formed between the final approach track and the runway centerline.
LOCALIZER TYPE DIRECTIONAL AID/LDA - A navigation aid, used for nonprecision instrument approaches with utility and accuracy comparable to a localizer but which is not a part of a complete Instrument Landing System and is not aligned with the runway.
LOCALIZER USABLE DISTANCE - The maximum distance from the localizer transmitter at a specified altitude, as verified by flight inspection, at which reliable course information is continuously received.
LOCAL TRAFFIC - Aircraft operating in the traffic pattern or within sight of the tower, or aircraft known to be departing or arriving from flight in local practice areas, or, aircraft executing practice instrument approaches at the airport. (See Traffic Pattern)
LOCATOR (ICAO) - A Low Medium/Frequency Non-directional Radio Beacon used as an aid to final approach.