chlo·​ro·​plast ˈklȯr-ə-ˌplast How to pronounce chloroplast (audio)
: a plastid that contains chlorophyll and is the site of photosynthesis see cell illustration
chloroplastic adjective

Examples of chloroplast in a Sentence

Recent Examples on the Web Previous evolutionary trees of plants built by scientists often used the genome of the chloroplast, the organelle that allows plants to perform photosynthesis. Veronique Greenwood, New York Times, 11 May 2024 Where the ‘powerhouse of the cell’ and chloroplasts come from Primary endosymbiosis happens when one microbial organism engulfs another. Laura Baisas, Popular Science, 18 Apr. 2024 After being swallowed by the slug, the algal cells continue to live in its digestive system, their chloroplasts photosynthesizing and producing energy, which is then used by the slug. Helen Sullivan, Smithsonian Magazine, 2 Apr. 2024 Two possibilities stand out: chloroplasts and mitochondria, both organelles that float around inside plant cells. Matthew Hutson, The New Yorker, 6 Feb. 2024 But photosynthesis, which occurs in chloroplasts, produces oxygen, and oxygen destroys nitrogenase. Matthew Hutson, The New Yorker, 6 Feb. 2024 That timing is similar to the origin of the photosynthetic cyanobacteria, which both continue to live independently and have been incorporated into plant cells as chloroplasts. John Timmer, Ars Technica, 3 Jan. 2024 Similarly, plant cells probably acquired chloroplasts, which capture the energy of sunlight, from some early parasite or symbiont. Discover Magazine, 11 Nov. 2019 The pump transferred protons from the cytoplasm to the compartment between the extra membrane and the chloroplast. Kevin Hartnett, Quanta Magazine, 6 July 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'chloroplast.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


International Scientific Vocabulary

First Known Use

1887, in the meaning defined above

Time Traveler
The first known use of chloroplast was in 1887

Dictionary Entries Near chloroplast

Cite this Entry

“Chloroplast.” Dictionary, Merriam-Webster, Accessed 17 Jun. 2024.

Kids Definition


chlo·​ro·​plast ˈklōr-ə-ˌplast How to pronounce chloroplast (audio)
: a cellular part that contains chlorophyll and is the location of photosynthesis

Medical Definition


chlo·​ro·​plast ˈklōr-ə-ˌplast, ˈklȯr- How to pronounce chloroplast (audio)
: a plastid that contains chlorophyll and is the site of photosynthesis and starch formation
chloroplastic adjective

More from Merriam-Webster on chloroplast

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