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 photosynthesize (audio) \ intransitive verb
photosynthetic \ ˌfō-​tō-​sin-​ˈthe-​tik How to pronounce photosynthetic (audio) \ adjective
photosynthetically \ ˌfō-​tō-​sin-​ˈthe-​ti-​k(ə-​)lē How to pronounce photosynthetically (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 This ecosystem is fuelled by what is known as marine snow—a steady shower of small, nutrient-rich particles that fall like manna from the ocean layers near the surface, where photosynthesis takes place. The Economist, "Palaeomicrobiology Researchers revive bacteria from the era of the dinosaurs," 1 Aug. 2020 Definitions for the processes of photosynthesis, respiration, transpiration and assimilation were particularly informative for me. Sally Peterson, oregonlive, "’The New Gardener’s Handbook” awakens intuitive skills, plant passion," 30 June 2020 There were huge tsunamis, submarine landslides, widespread wildfires, and likely insufficient sunlight to sustain photosynthesis after the asteroid hit, for example. Scott K. Johnson, Ars Technica, "Did huge eruptions actually help during the end-Cretaceous extinction?," 1 July 2020 More plant growth in the Arctic means that the vegetation is sequestering more CO2 via photosynthesis. Matt Simon, Wired, "Why the Arctic Is Warming So Fast, and Why That’s So Alarming," 23 June 2020 These algae live throughout the oceans—and most other damp places—and may conduct up to about a quarter of the photosynthesis in the world. Paige Embry, Scientific American, "Slimy Mudflat Biofilms Feed Migratory Birds—and Could Be Threatened," 17 June 2020 This tree growth can produce enough photosynthesis to feed the tree enough through the year to produce new growth the following year. oregonlive, "Vigilant gardener wonders if they spotted an invasive giant hornet - they didn’t: Ask an expert," 14 June 2020 This process, called photosynthesis, generates oxygen. Kristen Rogers, CNN, "6 reasons why bats aren't enemies: They help make tequila, and other surprising facts you may not know," 14 June 2020 Additionally, the temperatures reached over 100 degrees, which helped speed up ozone production by increasing photosynthesis in trees and plants. Erin Stone, azcentral, "Traffic was down in Phoenix, but ozone levels remained stubbornly high. What's happening?," 12 June 2020

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

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The first known use of photosynthesis was in 1898

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Last Updated

5 Aug 2020

Cite this Entry

“Photosynthesis.” Dictionary, Merriam-Webster, Accessed 8 Aug. 2020.

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How to pronounce photosynthesis (audio)

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

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More from Merriam-Webster on photosynthesis

Spanish Central: Translation of photosynthesis

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

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