light year

Definition from Wiktionary, a free dictionary

Contents 1 English 1.1 Etymology 1.2 Noun 1.2.1 Usage notes 1.2.2 Translations 1.3 See also

[edit] English

[edit] Etymology

light + year

[edit] Noun

Wikipedia

light year (plural light years)

1. (astronomy) A unit of length (abbreviation ly) equal to the distance light travels in one year; used to measure extremely large distances.
2. (in plural light years; figurative, informal) A very long way.

   The marathon runner in the lead is light years ahead of the one at the back.

3. (in plural light years; figurative, informal, nonstandard) A very long time.

   Some of Leonardo da Vinci’s inventions were light years ahead of their time.

[edit] Usage notes

• The light year is a unit of length, but because it contains the word year is sometimes assumed to be a unit of time. Its use in the figurative sense of "a very long time" is nonstandard; it is preferable to use an alternative term in this case.

[edit] Translations

[edit] See also

• parsec