: a disaccharide sugar C12H22O11 that is present in milk and yields glucose and galactose upon hydrolysis and yields especially lactic acid upon fermentation
Examples of lactose in a Sentence
Recent Examples on the Web
Milk Stout Nitro, Left Hand Brewing Co. The quintessential craft brewed milk stout in the U.S., Left Hand Brewing Co.’s Milk Stout Nitro’s ingredient list includes 2-row, crystal, and Munich malts, CTZ and U.S. Goldings hops, and lactose.
—
Erik Ofgang, Forbes, 8 Mar. 2025
Common causes of food intolerances include lactose, gluten, histamine, FODMAPs, and natural and synthetic food chemicals.
—Corinne Savides Happel, Verywell Health, 5 Mar. 2025
For example, lipase helps break down fats, protease targets proteins, and lactase breaks down the naturally occurring sugar called lactose in dairy products.
—Heather Sandison, Contributor, CNBC, 4 Mar. 2025
The bacteria, known as a yogurt culture, ferments the natural sugar lactose, which produces the creamy, tangy texture and flavor of yogurt.
—Allison Herries, Verywell Health, 10 Feb. 2025
See All Example Sentences for lactose
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Erik Ofgang, Forbes, 8 Mar. 2025
Common causes of food intolerances include lactose, gluten, histamine, FODMAPs, and natural and synthetic food chemicals.
—Corinne Savides Happel, Verywell Health, 5 Mar. 2025
For example, lipase helps break down fats, protease targets proteins, and lactase breaks down the naturally occurring sugar called lactose in dairy products.
—Heather Sandison, Contributor, CNBC, 4 Mar. 2025
The bacteria, known as a yogurt culture, ferments the natural sugar lactose, which produces the creamy, tangy texture and flavor of yogurt.
—Allison Herries, Verywell Health, 10 Feb. 2025
See All Example Sentences for lactose
Cite this Entry
“Lactose.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lactose. Accessed 13 Mar. 2025.
Copy CitationKids Definition
lactose
noun
lac·tose
ˈlak-ˌtōs 
: a sugar present in milk that breaks down to give glucose and galactose and on fermentation gives especially lactic acid
called also milk sugar
Medical Definition
lactose
noun
lac·tose
ˈlak-ˌtōs, -ˌtōz
: a disaccharide sugar C12H22O11 that is present in milk, yields glucose and galactose upon hydrolysis, yields especially lactic acid upon fermentation, and is used chiefly in foods, medicines, and culture media (as for the manufacture of penicillin)
called also milk sugar
Love words? Need even more definitions?
Merriam-Webster unabridged
Share