parsec

American  

[pahr-sek] / ˈpɑrˌsɛk /

noun

Astronomy.

1. a unit of distance equal to that required to cause a heliocentric parallax of one second of an arc, equivalent to 206,265 times the distance from the earth to the sun, or 3.26 light-years.

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parsec British  

/ ˈpɑːˌsɛk /

noun

1. a unit of astronomical distance equal to the distance from earth at which stellar parallax would be 1 second of arc; equivalent to 3.0857 × 10 ¹⁶ m or 3.262 light years

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parsec Scientific  

/ pär′sĕk′ /

1. A unit of astronomical length equal to 3.26 light-years. It is based on the distance from Earth at which a star would have a parallax of one second of arc. Its metric equivalent is about 30.8 trillion km (19.1 trillion mi). It is used in measuring distances in interstellar and intergalactic space. The closest star to Earth, Alpha Centauri, is about 1.3 parsecs away.

2. Compare astronomical unit light-year

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Etymology

Origin of parsec

First recorded in 1910–15; par(allax) + sec(ond) ²

Example Sentences

Converted into the astrophysical unit parsec, this corresponds to less than eight to ten parsecs.

From Science Daily • Nov. 2, 2023

No matter how many times I watch my favorite sci-fi films and series, I still can’t tell a parsec from a cylinder of drugstore plutonium.

From New York Times • Dec. 13, 2022

In the original movie, Han Solo claims that his ship “made the Kessel Run in less than 12 parsecs,” strongly implying that a parsec is a unit of time.

From Slate • Oct. 29, 2019

Back in the days when most of our distances came from parallax measurements, a parsec was a useful unit of distance, but it is not as intuitive as the light-year.

From Textbooks • Oct. 13, 2016

Or the light-year is equal to 0.31 parsec.

From Astronomy: The Science of the Heavenly Bodies by Todd, David Peck