: 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
While the levels are much lower than in milk, people with severe lactose intolerance or dairy allergies may still react to it.
—
Allison Herries, Verywell Health, 2 Apr. 2025
Simple carbs are natural, digestible sugars such as ones found in foods like milk (lactose), table sugar (sucrose) and fruit (fructose).
—Daryl Austin, USA Today, 29 Mar. 2025
Low in lactose, gluten free and made with all natural ingredients, LS Cream exudes style and luxury while staying true to its Caribbean heritage.
—Essence, 27 Mar. 2025
Cats that are intolerant to lactose may experience gas, vomiting or diarrhea after eating dairy products.
—David Faris, Newsweek, 27 Feb. 2025
See All Example Sentences for lactose
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Allison Herries, Verywell Health, 2 Apr. 2025
Simple carbs are natural, digestible sugars such as ones found in foods like milk (lactose), table sugar (sucrose) and fruit (fructose).
—Daryl Austin, USA Today, 29 Mar. 2025
Low in lactose, gluten free and made with all natural ingredients, LS Cream exudes style and luxury while staying true to its Caribbean heritage.
—Essence, 27 Mar. 2025
Cats that are intolerant to lactose may experience gas, vomiting or diarrhea after eating dairy products.
—David Faris, Newsweek, 27 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 22 Apr. 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
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