photosynthesis

noun pho·to·syn·the·sis \ ˌfō-tō-ˈsin(t)-thə-səs \

|Updated on: 21 Jul 2018

Editor's Note: photosynthesis Has Greek Roots

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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photosynthesize

play \ˌfō-tō-ˈsin(t)-thə-ˌsīz\ intransitive verb

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photosynthetic

play \ˌfō-tō-sin-ˈthe-tik\ adjective

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photosynthetically

play \ˌfō-tō-sin-ˈthe-ti-k(ə-)lē\ adverb

See photosynthesis defined for English-language learners

See photosynthesis defined for kids

Recent Examples of photosynthesis from the Web

When spring arrives, two primary factors create a change: the phytoplankton bloom removes CO2 from the water through photosynthesis, and the water gets warmer, making conditions more favorable for shell production.

— laine welch, Anchorage Daily News, "For Alaska sockeye salmon, record highs in Bristol Bay, record lows nearly everywhere else," 9 July 2018
That method often overlooks a range of factors, such as unknown natural gas leaks, traffic from outside the state, or the amount of photosynthesis by trees and other vegetation.

— david abel, BostonGlobe.com, "Emissions measures could be too low," 7 July 2018
It's earned its name because a small amount of light penetrates the region, yet not enough for photosynthesis.

— david grossman, Popular Mechanics, "NASA Is Stepping Into the Twilight Zone," 19 June 2018
The idea is that, through photosynthesis, eelgrass can absorb carbon and fight ocean acidification — which is caused by the sea taking in carbon dioxide from the atmosphere — and counter the effects of climate change.

— hillary davis, latimes.com, "Researchers in Newport optimistic that eelgrass can reduce carbon and acidity in seawater," 30 May 2018
In plants like rice and wheat that undergo what is known as C3 photosynthesis, higher levels of carbon dioxide may spur plants to produce more carbohydrates, which dilute some of the more nutritious components.

— New York Times, "How More Carbon Dioxide Can Make Food Less Nutritious," 23 May 2018
While most plants capture energy from the sun to grow and go through photosynthesis, this flower receives nutrition from the fungus without harming it.

— ashley strickland, CNN, "Meet the top 10 new species of 2018," 23 May 2018
When limbs are removed, a lot of needles are lost where photosynthesis would have occurred.

— debbie arrington, sacbee, "Will pruning stop falling branches?," 20 Apr. 2018
The trees grown in warmer conditions coped just as well as the others, and photosynthesis rates bounced back to normal after the heat wave passed, Drake and his colleagues reported online in February in Global Change Biology.

— yasemin saplakoglu, Scientific American, "Trees Sweat to Keep Cool," 12 Apr. 2018

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.

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.

Origin and Etymology of photosynthesis

New Latin

NEW! Time Traveler

First Known Use: 1898

in the meaning defined above

See Words from the same year

Other Botany Terms

annual, burgeon, chloroplast, nomenclature, succulent, sylvan, xylem

PHOTOSYNTHESIS Defined for English Language Learners

photosynthesis

noun

Definition of photosynthesis for English Language Learners

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

PHOTOSYNTHESIS Defined for Kids

photosynthesis

noun pho·to·syn·the·sis \ ˌfō-tə-ˈsin-thə-səs \

Definition of photosynthesis for Students

: 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

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photosynthetic

\-sin-ˈthe-tik\ adjective

photosynthetic activity

Medical Dictionary

photosynthesis

noun pho·to·syn·the·sis \ ˌfōt-ō-ˈsin(t)-thə-səs \

medical Definition of photosynthesis

plural photosyntheses

: 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

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photosynthesize

play \-ˌsīz\ also British photosynthesise intransitive verb photosynthesized also British photosynthesised; photosynthesizing also British photosynthesising

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