pho·​to·​syn·​the·​sis | \ ˌfō-tō-ˈsin(t)-thə-səs How to pronounce photosynthesis (audio) \

Definition of photosynthesis

: synthesis of chemical compounds with the aid of radiant energy and especially light especially : formation of carbohydrates from carbon dioxide and a source of hydrogen (such as water) in the chlorophyll-containing cells (as of green plants) exposed to light

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Other Words from photosynthesis

photosynthesize \ ˌfō-​tō-​ˈsin(t)-​thə-​ˌsīz How to pronounce photosynthesis (audio) \ intransitive verb
photosynthetic \ ˌfō-​tō-​sin-​ˈthe-​tik How to pronounce photosynthesis (audio) \ adjective
photosynthetically \ ˌfō-​tō-​sin-​ˈthe-​ti-​k(ə-​)lē How to pronounce photosynthesis (audio) \ adverb

Photosynthesis Has Greek Roots

The Greek roots of photosynthesis combine to produce the basic meaning "to put together with the help of light". Photosynthesis is what first produced oxygen in the atmosphere billions of years ago, and it's still what keeps it there. Sunlight splits the water molecules (made of hydrogen and oxygen) held in a plant's leaves and releases the oxygen in them into the air. The leftover hydrogen combines with carbon dioxide to produce carbohydrates, which the plant uses as food—as do any animals or humans who might eat the plant.

Examples of photosynthesis in a Sentence

Recent Examples on the Web Their design was initially inspired by photosynthesis – the process by which plants transform sunlight into energy via the green pigment (chlorophyll) found in their leaves. Laurie Winkless, Forbes, "Solar City? Turning Buildings Into Power Plants," 20 Apr. 2021 Through the biogenic cycle, plants can use methane emissions to perform photosynthesis and fix the carbon back into cellulose, which cattle can then consume as part of a continuing, closed-loop cycle that is roughly a decade in length. Brian Devore, Star Tribune, "Counterpoint: Don't turn to animal-free meat; just let the animals out," 28 Apr. 2021 Regenerative farming is about cultivating healthy soil microbiology and maximizing photosynthesis, which presents unique challenges in the arid Southwest since both require water. Lisa Deaderick, San Diego Union-Tribune, "Through Solidarity Farm, cultivating fruitful relationships between the land and the people they feed," 17 Apr. 2021 Basically, in cases where a treatment increased photosynthesis, the tree dropped its leaves sooner. Ula Chrobak, Popular Science, "Climate change is affecting fall foliage, but not in the way you think," 30 Nov. 2020 This occurs not just through photosynthesis but the way the oak partners with a beneficial soil fungi named mycorrhizae, which develops over several years to effectively extend the root system of its host plant. Washington Post, "The sturdy, steadfast oak is the perfect tree for troubled times," 14 Apr. 2021 Trees absorb carbon dioxide from the air and through photosynthesis. Liz Allen, Forbes, "Scientists Find Underwater Plants Can Combat Ocean Acidification," 12 Apr. 2021 This lets the slugs sustain themselves, at least partially, on the sugars the chloroplasts produce through photosynthesis. New York Times, "Meet the Sea Slugs That Chop Off Their Heads and Grow New Bodies," 8 Mar. 2021 In the algae that the animals eat, photosynthesis hums along in structures known as chloroplasts. Matt Simon, Wired, "Hey, So These Sea Slugs Decapitate Themselves and Grow New Bodies," 8 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'photosynthesis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of photosynthesis

1898, in the meaning defined above

History and Etymology for photosynthesis

New Latin

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Time Traveler for photosynthesis

Time Traveler

The first known use of photosynthesis was in 1898

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Last Updated

14 May 2021

Cite this Entry

“Photosynthesis.” Dictionary, Merriam-Webster, Accessed 14 May. 2021.

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More Definitions for photosynthesis



English Language Learners Definition of photosynthesis

biology : the process by which a green plant turns water and carbon dioxide into food when the plant is exposed to light


pho·​to·​syn·​the·​sis | \ ˌfō-tə-ˈsin-thə-səs How to pronounce photosynthesis (audio) \

Kids Definition of photosynthesis

: the process by which green plants and a few other organisms (as some protists) form carbohydrates from carbon dioxide and water in the presence of light

Other Words from photosynthesis

photosynthetic \ -​sin-​ˈthe-​tik \ adjective photosynthetic activity


pho·​to·​syn·​the·​sis | \ ˌfōt-ō-ˈsin(t)-thə-səs How to pronounce photosynthesis (audio) \
plural photosyntheses

Medical Definition of photosynthesis

: synthesis of chemical compounds with the aid of light sometimes including the near infrared or near ultraviolet especially : the formation of carbohydrates from carbon dioxide and a source of hydrogen (as water) in chlorophyll-containing cells (as of green plants) exposed to light involving a photochemical release of oxygen through the decomposition of water followed by various enzymatic synthetic reactions that usually do not require the presence of light

Other Words from photosynthesis

photosynthesize \ -​ˌsīz How to pronounce photosynthesis (audio) \ also British photosynthesise intransitive verb photosynthesized also British photosynthesised; photosynthesizing also British photosynthesising
photosynthetic \ -​sin-​ˈthet-​ik How to pronounce photosynthesis (audio) \ adjective
photosynthetically \ -​i-​k(ə-​)lē How to pronounce photosynthesis (audio) \ adverb

More from Merriam-Webster on photosynthesis

Nglish: Translation of photosynthesis for Spanish Speakers Encyclopedia article about photosynthesis

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