Definitions of astronomy unit
1
n a linear unit used for astronomical distances
 Types:
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light year, lightyear
the distance that light travels in a vacuum in 1 year; 5.88 trillion miles or 9.46 trillion kilometers

light hour
the distance light travels in a vacuum in one hour; approximately one billion kilometers

light minute
the distance light travels in a vacuum in one minute; approximately 18 million kilometers

light second
the distance light travels in a vacuum in one second; approximately 300,000 kilometers

AU, Astronomical Unit
a unit of length used for distances within the solar system; equal to the mean distance between the Earth and the Sun (approximately 93 million miles or 150 million kilometers)

parsec, secpar
a unit of astronomical length based on the distance from Earth at which stellar parallax is 1 second of arc; equivalent to 3.262 light years
 Type of:

linear measure, linear unit
a unit of measurement of length