Definition of Light year

1. Noun. The distance that light travels in a vacuum in 1 year; 5.88 trillion miles or 9.46 trillion kilometers.

Exact synonyms: Light-year
Generic synonyms: Astronomy Unit
Terms within: Light Hour, Light Minute, Light Second

Definition of Light year

1. Noun. (astronomy) A unit of length (''abbreviation'' ly; equal to just under 10 trillion kilometres (1016 metres)) equal to the distance light travels in one year; used to measure extremely large distances. ¹

2. Noun. (''in plural '''light years'''; figurative, informal'') A very long way. ¹

3. Noun. (''in plural '''light years'''; figurative, informal, nonstandard'') A very long time. ¹

¹ Source: wiktionary.com

Lexicographical Neighbors of Light Year

light switch
light switches
light table
light time
light touch
light treatment
light unit
light up
light upon
light verb
light verbs
light water
light welterweight
light whipping cream
light year (current term)
light years
lightable
lightbar
lightbars
lightboard
lightboards
lightbox
lightboxes
lightbulb
lightbulbs
lightclock
lightcone
lightcones
lightcurve

Literary usage of Light year

Below you will find example usage of this term as found in modern and/or classical literature:

1. Appletons' Annual Cyclopædia and Register of Important Events of the Year (1903)
"If the light year of a star having a parallax of 1" be divided by the assumed parallax of any other star the result gives the distance in light years. ..."

2. Merriam-Webster's Dictionary of English Usage by Inc. Merriam-Webster (1994)
"—Susan Rice, Media & Methods, October 1970 light-year In scientific usage, a light-year is a unit of distance equal to about ..."

3. Science of Home and Community: A Text-book in General Science by Gilbert Haven Trafton (1919)
"So astronomers have devised a new unit which is called the light year. ... This distance, called the light year, is taken as the unit in measuring distances ..."

4. Manual of Astronomy: A Text-book by Charles Augustus Young (1902)
"The light-year bears to the astronomical unit almost exactly the same ratio as the mile to the inch. ..."

5. The New International Encyclopaedia edited by Daniel Coit Gilman, Harry Thurston Peck, Frank Moore Colby (1906)
"It is the linear space traversed by light in one year, and as light moves at the rate of about 186.600 miles per second, the light year furnishes a linear ..."

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