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[klawr-uh-fil, klohr-] /ˈklɔr ə fɪl, ˈkloʊr-/
noun, Botany, Biochemistry
the green coloring matter of leaves and plants, essential to the production of carbohydrates by photosynthesis, and occurring in a bluish-black form, C 55 H 72 MgN 4 O 5 (chlorophyll a) and a dark-green form, C 55 H 70 MgN 4 O 6 (chlorophyll b)
Also, chlorophyl.
1810-20; chloro-1 + -phyll
Related forms
chlorophylloid, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for chlorophyll
  • Light breaks down the chlorophyll in herbs and makes yellow spots that often turn white.
  • Plant chlorophyll, for example, absorbs and reflects all wavelengths of light except green.
  • Spider mites congregate on the underside of leaves, sip on plant fluids and remove chlorophyll.
  • chlorophyll, however, breaks down easily in bright sunlight.
  • As winter encroaches, trees cut off the supply of chlorophyll to their leaves.
  • The glowing is the result of a chemical that's created as the green chlorophyll in the peel breaks down.
  • High concentrations of chlorophyll gave it a rich olive color.
  • If you could design a plant from scratch, you'd probably use silicon films instead of chlorophyll to collect sunlight.
  • But the chlorophyll's not involved in charge transport.
  • In the fall, the green chlorophyll in a tree fades away, while the tree actively builds new pigments to turn it red or yellow.
British Dictionary definitions for chlorophyll


the green pigment of plants and photosynthetic algae and bacteria that traps the energy of sunlight for photosynthesis and exists in several forms, the most abundant being chlorophyll a (C55H72O5N4Mg): used as a colouring agent in medicines or food (E140)
Derived Forms
chlorophylloid, adjective
chlorophyllous, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for chlorophyll

green-colored stuff in plants, 1819, from French chlorophyle (1818), coined by French chemists Pierre-Joseph Pelletier (1788-1842) and Joseph Bienaimé Caventou (1795-1877) from Greek khloros "pale green" (see Chloe) + phyllon "a leaf" (see folio).

Online Etymology Dictionary, © 2010 Douglas Harper
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chlorophyll in Medicine

chlorophyll chlo·ro·phyll or chlo·ro·phyl (klôr'ə-fĭl)
Any of a group of related green pigments found in photosynthetic cells that converts light energy into ATP and other forms of energy needed for biochemical processes; it is found in green plants, brown and red algae, and certain aerobic and anaerobic bacteria.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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chlorophyll in Science
Any of several green pigments found in photosynthetic organisms, such as plants, algae, and cyanobacteria. At its molecular core, chlorophyll has a porphyrin structure but contains a magnesium atom at its center and a long carbon side chain. Chlorophyll absorbs red and blue wavelengths of light, but reflects green. When it absorbs light energy, a chlorophyll molecule enters a higher energy state in which it easily gives up an electron to the first available electron-accepting molecule nearby. This electron moves through a chain of acceptors and is ultimately used in the synthesis of ATP, which provides chemical energy for plant metabolism. Plants rely on two forms of chlorophyll, chlorophyll a (C66H72MgN4O5) and chlorophyll b (C66H70MgN4O6), which have slightly different light absorbing properties. All plants, algae, and cyanobacteria have chlorophyll a, since only this compound can pass an electron to acceptors in oxygen-producing photosynthetic reactions. Chlorophyll b absorbs light energy that is then transferred to chlorophyll a. Several protist groups such as brown algae and diatoms lack chlorophyll b but have another pigment, chlorophyll c, instead. Other closely related pigments are used by various bacteria in photosynthetic reactions that do not produce oxygen. See more at photosynthesis.

Our Living Language  : From its name, one might think that chlorophyll has chlorine in it, but it doesn't. The chloro- of chlorophyll comes from the Greek word for "green"; chlorophyll in fact is the chemical compound that gives green plants their characteristic color. The name of the chemical element chlorine comes from the same root as the prefix chloro-, and is so called because it is a greenish-colored gas.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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chlorophyll in Culture
chlorophyll [(klawr-uh-fil)]

The complex chemical that gives a plant its green color and plays an important role in the conversion of sunlight into energy for the plant. (See photosynthesis.)

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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