the apparent magnitude of the faintest objects that can be seen given the local observing conditions and any telescope, film, or other detector you may be using

The magnitude of the dimmest star you can see overhead on a given night.

A measure of observing conditions (sky transparency) by identifying the faintest stars visible.

A measure of the darkness of the sky during a meteor watch. It is defined as the magnitude of the faintest star visible in the area of sky under observation

Generally denotes the faintest star visible during an observation and evaluates the quality of the sky as well as the observing technique. The magnitude of the faintest meteor visible can be different from the stellar limiting magnitude, particularly for photographic and video observations. Visual observations assume about the same limiting magnitudes for stars and meteors. See also: Photographic observations, Video observations, Visual observations

The limiting magnitude is the magnitude of the dimmest star that you can see by the zenith (overhead). It is determined by weather and viewing techniques.

Limiting magnitude is the faintest apparent magnitude detectable or detected by a given instrument.