(space science) A mountain peak, on a solid, non-luminous celestial body, which experiences continuous or near-continuous illumination due to a combination of high altitude, very high latitude, and being on a celestial body with very low axial tilt.

(astronomy, physics) A unit of length equal to the distance light travels in one millisecond: approximately 300 kilometers

plural of large light cruiser

(military, nautical, historical) A very large, fast warship with a relatively-shallow draft and minimal belt armor, carrying a relatively-small number of very heavy guns; sometimes classed as a type of battlecruiser.

(video games) A general hardware failure in the Playstation 3 video game console and related to an issue on the motherboard, the power supply, commonly caused by a degraded capacitor.

(US, military slang, used by fighter pilots) To take off.

A light-emitting diode constructed from a thin film of an organic compound.

Obsolete form of trip the light fantastic.

(simile) To fall asleep quickly.

(idiomatic) To take a position which is harmful to one's own interests.