One of a race of elves who live above ground and are radiant. / (Norse mythology) A daylight dwelling elf or nature spirit (as opposed to the underground dwelling dark elves or dwarves).

(physics) The speed of electromagnetic radiation; in a perfect vacuum it is defined as 299,792,458 metres per second / (colloquial, figuratively) A very rapid speed.

(intransitive, cricket, of the umpires) To ask the batsmen if they wish to continue playing in conditions of poor light. If they do not, play is suspended for bad light.

(cricket) A weather condition where the light is so poor that the umpires feel that to continue playing would be dangerous. / (figuratively) An unfavourable presentation.

A source of illumination.

(cricket) The lighter of the rollers used for flattening the pitch between innings.

synchrotron radiation

A traffic light in its green state (indicating that vehicles may proceed). / (idiomatic) Approval, or permission to proceed.

(physics) The part of the electromagnetic spectrum, between infrared and ultraviolet, that is visible to the human eye.

(uncountable) Light, having a mixture of frequencies, being perceived as having no specific colour; such as sunlight. / (countable) A white-coloured light or lamp