lac·​tose | \ ˈlak-ˌtōs How to pronounce lactose (audio) , -ˌtōz\

Definition of lactose

: 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

That Got Away is a Milkshake IPA brewed with pineapple, coconut and lactose at 8.4% alcohol and 20 IBUs. Saturday, June 15: Granite City Food & Brewery will offer $5 growler fills of any growler on Father’s Day weekend. Marc Bona,, "Beer calendar: Platform’s 5th anniversary party, Great Lakes dinner and release, more," 3 June 2019 In general, fresher cheeses contain more lactose than aged cheeses, which means cheeses like feta and ricotta, my old favorites, are higher in lactose, and now my enemy. Christian Allaire, Vogue, "I Gave Up Dairy—And My Adult Acne Vanished in Under a Month," 28 July 2018 IPAs brewed with lactose for extra body have also started to multiply (after Tired Hands became the first local to make it). Craig Laban,, "2018 Brewvitational standouts: Peter, haze and pucker," 10 May 2018 The process of fermenting milk into cheese also reduces its lactose content, because much of it drains away with the liquid whey. Kiona N. Smith, Ars Technica, "Early cheese making may have helped lactose-intolerant farmers spread," 14 Sep. 2018 Polar bear milk has almost ten times as much fat and protein as cow's milk, almost no lactose. Bob Gathany,, "Up in the air at the Huntsville Community Kite Festival," 4 Mar. 2018 To make it, dairy producers have long employed the help of Streptococcus thermophilus, a bacteria that gobbles up the lactose in milk and poops out lactic acid. Megan Molteni, WIRED, "The WIRED Guide to Crispr," 27 Apr. 2018 Glutard, then, is a disparaging term for a person who doesn’t eat gluten, lactard for someone who can’t tolerate lactose, and libtard for a liberal. Melissa Mohr, The Christian Science Monitor, "When good words turn bad," 28 June 2018 Nut and seed milks are a delicious lactose-free alternative to traditional dairy milk, and they can be used in a variety of recipes that require the real thing. Time, "Weekend Recipe: Your Guide to Creating Dairy-Free Nut, Seed and Rice Milks," 22 June 2018

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

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First Known Use of lactose

1847, in the meaning defined above

History and Etymology for lactose

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Statistics for lactose

Last Updated

16 Jun 2019

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Time Traveler for lactose

The first known use of lactose was in 1847

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More Definitions for lactose



English Language Learners Definition of lactose

chemistry : a type of sugar that is present in milk


lac·​tose | \ ˈlak-ˌtōs How to pronounce lactose (audio) \

Kids Definition of lactose

: a sugar that is found in milk


lac·​tose | \ ˈlak-ˌtōs, -ˌtōz How to pronounce lactose (audio) \

Medical Definition of lactose

: 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

More from Merriam-Webster on lactose

Rhyming Dictionary: Words that rhyme with lactose Encyclopedia article about lactose

Comments on lactose

What made you want to look up lactose? Please tell us where you read or heard it (including the quote, if possible).


to take the place or position of

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