chlorophyll

noun

chlo·​ro·​phyll ˈklȯr-ə-ˌfil 

-fəl

1

: the green photosynthetic pigment found chiefly in the chloroplasts of plants and occurring especially as a blue-black ester C₅₅H₇₂MgN₄O₅ or a dark green ester C₅₅H₇₀MgN₄O₆

called also respectively chlorophyll a, chlorophyll b

2

: a waxy green chlorophyll-containing substance extracted from green plants and used as a coloring agent or deodorant

chlorophyllous

ˌklȯr-ə-ˈfi-ləs 

adjective

Examples of chlorophyll in a Sentence

Recent Examples on the Web

Sunlight would otherwise activate the plants’ chlorophyll and turn the asparagus green. —Yolanda Evans, AFAR Media, 21 Mar. 2025

The magnesium and calcium in the Epsom salt encourage the leaves to make more chlorophyll. —Leanne Potts, Better Homes & Gardens, 19 Mar. 2025

By the end of March, however, the microalgae’s carbon uptake had jumped, along with the number of cells and the concentration of chlorophyll—proxies for growth and photosynthesis. —Asher Elbein, WIRED, 2 Mar. 2025

To everyone’s surprise, the phytoplankton were not asleep either: Hoppe measured higher levels of the pigment chlorophyll — a useful proxy for active photosynthesis — in the seawater than anyone expected. —Quanta Magazine, 29 Jan. 2025

Word History

Etymology

French chlorophylle, from chlor- + Greek phyllon leaf — more at blade

First Known Use

1819, in the meaning defined at sense 1

Kids Definition

chlorophyll

noun

chlo·​ro·​phyll ˈklōr-ə-ˌfil 

ˈklȯr-,

-fəl

: the green coloring matter that is found chiefly in the chloroplasts of plants and is necessary for photosynthesis

Medical Definition

chlorophyll

noun

chlo·​ro·​phyll ˈklōr-ə-ˌfil, ˈklȯr-, -fəl 

1

: the green photosynthetic coloring matter of plants found in chloroplasts and made up chiefly of a blue-black ester C₅₅H₇₂MgN₄O₅ and a dark green ester C₅₅H₇₀MgN₄O₆

called also respectively chlorophyll a, chlorophyll b

2

: a waxy green chlorophyll-containing substance extracted from green plants and used as a coloring agent or deodorant

chlorophyllous

ˌklōr-ə-ˈfil-əs, ˌklȯr- 

adjective

also chlorophyllose

-ˈfil-ˌōs, -(ˌ)fil-ˈ