light year
UK /ˈlaɪt.jɪə/ · US /ˈlaɪt.jɪɹ/ noun
Forms light years ly lightyear light-year
- noun (astronomy) A unit of length used to measure extremely large distances, equal to approximately 9.46 trillion kilometres 10 trillion kilometres (10¹⁶ metres), equivalent to the distance light travels in one Julian year.
- noun (chiefly in the plural, informal, figurative) A very long way. “The marathon runner in the lead is light years ahead of the one at the back.”
- noun (chiefly in the plural, informal, figurative) A very long time. “Some of Leonardo da Vinci’s inventions were light years ahead of their time.”
Synonyms
Sources: Wiktionary · WordNet 3.0 — from the Wiktionary entry “light year”, CC BY-SA 4.0. Details