chlorophyll

American  

[klawr-uh-fil, klohr-] / ˈklɔr ə fɪl, ˈkloʊr- /

Or chlorophyl

noun

Botany, Biochemistry.

• chlorophylls
  plural

1. 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.

---

chlorophyll British  

/ ˈklɔːrəfɪl /

noun

1. 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 (C 55 H 72 O 5 N 4 Mg): used as a colouring agent in medicines or food ( E140 )

---

chlorophyll Scientific  

/ klôr′ə-fĭl /

1. 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 (C ₆₆ H ₇₂ MgN ₄ O ₅) and chlorophyll b (C ₆₆ H ₇₀ MgN ₄ O ₆), 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.

2. See more at photosynthesis

---

chlorophyll Cultural  

1. 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.)

---

Word History

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.

Other Word Forms

Derived Forms

• chlorophylloid
  adjective
• chlorophyllous
  adjective

Inflected Forms

Nouns

• chlorophylls
  plural

Etymology

Origin of chlorophyll

First recorded in 1810–20; chloro- ¹ + -phyll

Compare meaning

How does chlorophyll compare to similar and commonly confused words? Explore the most common comparisons:

• chlorophyll vs. chloroplast

Explanation

Chlorophyll makes plants green. It's basically a group of green pigments used by organisms that convert sunlight into energy via photosynthesis. First used in 1819, the noun chlorophyll derives from the Greek words khloros, meaning "pale green" and phyllon, meaning "a leaf." Plants use chlorophyll to trap energy from the sun. Without this energy, plants would be unable to initiate the process of photosynthesis, which converts water and carbon dioxide into starches that plants can use for food.

Example Sentences

See Examples For:

chlorophyll chlorophylls

Fruit stored at 30°C yellowed rapidly, while mangoes kept at 12°C maintained their color longer because chlorophyll breakdown slowed significantly.

From Science Daily ● May 23, 2026

That can make it far cheaper to plant than corn, which needs high amounts of nitrogen to produce the chlorophyll essential for photosynthesis.

From The Wall Street Journal ● Apr. 30, 2026

The team measured how much light the chlorophyll absorbed in moss samples of known ages.

From Science Daily ● Mar. 6, 2026

In spinach, traces of harmful chlorophyll triplet states remained.

From Science Daily ● Oct. 22, 2025

She was pretty in a dryad-y way, with her purple gossamer dress and her elfish face, but her eyes were green-tinted with chlorophyll from crying.

From "The Last Olympian" by Rick Riordan

They found that the helical fibers formed by the second-generation dendron chlorophylls exhibited a highly ordered structure, while the third-generation dendron chlorophylls displayed a more homogeneous, spherical shape.

From Science Daily ● Nov. 21, 2024

There are a few algae species that produce chlorophylls a or b like land plants, instead of c.

From Science Daily ● Mar. 6, 2024

There are five major chlorophylls: a, b, c and d and a related molecule found in prokaryotes called bacteriochlorophyll.

From Textbooks ● Jun. 9, 2022

Researchers are also studying the infrared-absorbing chlorophylls made by some types of photosynthetic cyanobacteria2.

From Nature ● Apr. 25, 2017

Solutions of the chlorophylls are fluorescent, being green by transmitted, and red by reflected light.

From The Chemistry of Plant Life by Roscoe Wilfred Thatcher