: a pentose C5H10O5 found especially in the dextrorotatory form as a component of many nucleosides (such as adenosine and guanosine) especially in RNA
Examples of ribose in a Sentence
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The study’s findings also indicate that the sugar ribose, which is one of the building blocks for RNA, may have been more widespread in the early solar system than deoxyribose, a building block of DNA.
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Toria Sheffield, PEOPLE, 6 Dec. 2025
For life on Earth, the sugars deoxyribose – which the researchers did not detect – and ribose are key building blocks of DNA and RNA, respectively.
—Eric Lagatta, USA Today, 4 Dec. 2025
Analyzing pristine fragments of the asteroid delivered to Earth by NASA's OSIRIS-REx spacecraft in 2023, a team led by Yoshihiro Furukawa of Tohoku University in Japan found ribose, a crucial building block of RNA, and glucose, an energy-rich sugar used by nearly all life on Earth.
—Sharmila Kuthunur, Space.com, 3 Dec. 2025
Other names commonly used for ribose include ribose sugar and simply ribose.
—Lauren Manaker Ms, Rdn, Health, 19 July 2024
For example, all living things only use the right-handed form of the sugar ribose to form the backbone of DNA, giving it that the signature twist.
—Nathaniel Scharping, Discover Magazine, 14 June 2016
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Toria Sheffield, PEOPLE, 6 Dec. 2025
For life on Earth, the sugars deoxyribose – which the researchers did not detect – and ribose are key building blocks of DNA and RNA, respectively.
—Eric Lagatta, USA Today, 4 Dec. 2025
Analyzing pristine fragments of the asteroid delivered to Earth by NASA's OSIRIS-REx spacecraft in 2023, a team led by Yoshihiro Furukawa of Tohoku University in Japan found ribose, a crucial building block of RNA, and glucose, an energy-rich sugar used by nearly all life on Earth.
—Sharmila Kuthunur, Space.com, 3 Dec. 2025
Other names commonly used for ribose include ribose sugar and simply ribose.
—Lauren Manaker Ms, Rdn, Health, 19 July 2024
For example, all living things only use the right-handed form of the sugar ribose to form the backbone of DNA, giving it that the signature twist.
—Nathaniel Scharping, Discover Magazine, 14 June 2016
Cite this Entry
“Ribose.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ribose. Accessed 31 Dec. 2025.
Copy CitationKids Definition
ribose
noun
ri·bose
ˈrī-ˌbōs 
: a sugar that has five carbon atoms and five oxygen atoms in each molecule and is part of RNA compare deoxyribose
Medical Definition
ribose
noun
ri·bose
ˈrī-ˌbōs, -ˌbōz
: a pentose C5H10O5 found especially in the levorotatory D-form as a constituent of a number of nucleosides (as adenosine, cytidine, and guanosine) especially in RNA
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