from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The fraction of incident electromagnetic radiation reflected by a surface, especially of a celestial body.
  • n. The spongy white tissue on the inside of the rind of citrus fruit.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The fraction of incident light or radiation reflected by a surface or body, commonly expressed as percentage.
  • n. The whitish inner portion of the rind of citrus fruits that is a source of pectin, commonly referred to as the pith.

from the GNU version of the Collaborative International Dictionary of English

  • n. Whiteness.

from The Century Dictionary and Cyclopedia

  • n. Whiteness; specifically, the proportion of light falling on a surface and irregularly reflected from it: as, the albedo of the moon.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. the ratio of reflected to incident light


Late Latin albēdō, whiteness, from Latin albus, white; see albho- in Indo-European roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin albēdō ("whiteness"). (Wiktionary)



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  • "The answer is always the same: albedo."

    Mike Brown, How I Killed Pluto and Why It Had It Coming (New York: Spiegel & Grau, 2010)

    October 11, 2015

  • Some five years after learning it here, I finally spotted it in the wild in Ender’s Game. :-D

    October 14, 2013

  • Great article, brtom--thanks for posting this.

    January 3, 2008

  • I was enjoying the book until I came across the following sentence: "The albedo of Gilgit's brown, barren hills is high, and the heat from the sun just seems to bounce around the bowl that the town sits in." James Meek

    January 3, 2008