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

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 The photosynthesis on these early reefs drove the creation of an oxygen-rich atmosphere that would sustain advanced life. Rowan Moore Gerety, Wired, 5 Apr. 2022 The process of photosynthesis can begin, turning sunlight, water and oxygen into sugars. Beth Botts,, 13 Mar. 2022 While the Weddell Sea is covered with sea ice all year round, the ice is relatively thin -- three feet thick -- meaning that photosynthesis can still take place and life can thrive. Katie Hunt, CNN, 13 Jan. 2022 After all, plants make their own food from photosynthesis. Arricca Elin Sansone, House Beautiful, 10 Mar. 2021 More photosynthesis means more carbon dioxide is siphoned out of the atmosphere and excreted back into the earth as organic compounds. Tim Neville, Outside Online, 27 Oct. 2020 According to Jim Myers, a professor of vegetable breeding at Oregon State, the stored carbohydrates that the plant created through photosynthesis during the sunny months convert to soluble sugars once the temperature drops. Jonathan Kauffman, Bon Appétit, 13 Apr. 2022 Such artificial cells could be used as living factories for the production of biofuels or drugs, or as hyperefficient sites of artificial photosynthesis. James Somers, The New Yorker, 28 Feb. 2022 While the earlier snowmelt was stimulating plants’ productivity in June, that productivity began to taper off in July – normally their peak season for photosynthesis. Donatella Zona, The Conversation, 29 Mar. 2022 See More

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.

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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Dictionary Entries Near photosynthesis



photosynthetic ratio

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Statistics for photosynthesis

Last Updated

14 May 2022

Cite this Entry

“Photosynthesis.” Dictionary, Merriam-Webster, Accessed 24 May. 2022.

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More Definitions for photosynthesis


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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