ga·​lac·​tose gə-ˈlak-ˌtōs How to pronounce galactose (audio)
: a sugar C6H12O6 less soluble and less sweet than glucose

Example Sentences

Recent Examples on the Web On Friday, the state lab ran its first screen of Garrett's blood, which showed 13 milligrams of galactose., 29 Apr. 2022 Generally, lactose-free milk is made by adding the enzyme lactase to regular milk, which breaks down the milk sugar lactose into its two component sugars, glucose and galactose. Dr. Keith Roach, oregonlive, 1 Dec. 2021 Lactose is the carbohydrate component of milk – a disaccharide composed of D-glucose and D-galactose. Science & Food, Discover Magazine, 21 July 2015 This type of linkage makes the sialic acid and galactose stick straight up. Quanta Magazine, 25 Feb. 2020 Avian influenzas prefer a linkage known as an α2,3 linkage, in which the sialic acid binds to the sugar galactose via a specific carbon atom. Quanta Magazine, 25 Feb. 2020 The second is disaccharides, which are just two of these single sugar molecules linked together: sucrose, or table sugar (glucose + fructose); lactose, or milk sugar (glucose + galactose); and maltose, or malt sugar (glucose + glucose). Carolyn L. Todd, SELF, 24 June 2019 The first is monosaccharides, or single sugar molecules, which include fructose, galactose, and glucose. Carolyn L. Todd, SELF, 24 June 2019 Mano a mannose The authors compared the tumor cells' growth on a variety of sugars: glucose, fructose, frucose, galactose, and mannose. Diana Gitig, Ars Technica, 21 Nov. 2018 See More

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

Word History


borrowed from French, from Greek galakt-, gála "milk" + French -ose -ose entry 2; from the occurrence of the sugar in milk — more at galaxy

First Known Use

1862, in the meaning defined above

Time Traveler
The first known use of galactose was in 1862

Dictionary Entries Near galactose

Cite this Entry

“Galactose.” Dictionary, Merriam-Webster, Accessed 27 Mar. 2023.

Kids Definition


ga·​lac·​tose gə-ˈlak-ˌtōs How to pronounce galactose (audio)
: a sugar that is less easily dissolved and is less sweet than glucose

Medical Definition


ga·​lac·​tose gə-ˈlak-ˌtōs, -ˌtōz How to pronounce galactose (audio)
: an optically active sugar C6H12O6 that is less soluble and less sweet than glucose and is known in dextrorotatory, levorotatory, and racemic forms

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