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galactose

American  
[guh-lak-tohs] / gəˈlæk toʊs /

noun

Chemistry.

  1. a white, crystalline, water-soluble hexose sugar, C 6 H 12 O 6 , obtained in its dextrorotatory form from milk sugar by hydrolysis and in its levorotatory form from mucilages.

galactose British  
/ -əʊs, ɡəˈlæktəʊz /

noun

  1. a white water-soluble monosaccharide found in lactose. Formula: C 6 H 12 O 6

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
galactose Scientific  
/ gə-lăk′tōs′ /

  1. A monosaccharide commonly occurring in lactose and in certain pectins, gums, and mucilages. Chemical formula: C 6 H 12 O 6 .

Etymology

Origin of galactose

First recorded in 1865–70; galact- + -ose 2

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

This enzyme enables the bacteria to generate galactose directly from glucose.

From Science Daily • Jan. 13, 2026

Two major carbohydrate components were studied: fucose and galactose.

From Science Daily • Jan. 9, 2026

Lactose, or milk sugar, is a disaccharide made of two simple sugars – glucose and galactose – in a 1:1 ratio.

From Salon • Mar. 28, 2024

Following her illness, Mills was diagnosed with galactosaemia, a rare genetic disorder affecting up to one in 45,000 babies which prevents her body from turning galactose into glucose.

From BBC • Jan. 9, 2024

Like glucose and fructose, galactose seems to promote the production of glycogen in the body.

From Dietetics for Nurses by Proudfit, Fairfax T.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.