lactose

[ lak-tohs ]
/ ˈlæk toʊs /

noun

Biochemistry. a disaccharide, C12H22O11, present in milk, that upon hydrolysis yields glucose and galactose.
a white, crystalline, sweet, water-soluble commercial form of this compound, obtained from whey and used in infant feedings, in confections and other foods, in bacteriological media, and in pharmacology as a diluent and excipient.

Nearby words

  1. lactonic,
  2. lactonize,
  3. lactoprotein,
  4. lactorrhea,
  5. lactoscope,
  6. lactosuria,
  7. lactotherapy,
  8. lactotropin,
  9. lactovegetarian,
  10. lacuna

Origin of lactose

First recorded in 1855–60; lact- + -ose2


Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for lactose


British Dictionary definitions for lactose

lactose

/ (ˈlæktəʊs, -təʊz) /

noun

a white crystalline disaccharide occurring in milk and used in the manufacture of pharmaceuticals and baby foods. Formula: C 12 H 22 O 11Also called: milk sugar
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

Word Origin and History for lactose

lactose

n.

sugar from milk, 1858, from French, coined by French chemist Marcelin-Pierre-Eugène Berthelot (1827-1907) from Latin lac (genitive lactis) "milk" (see lactation) + chemical suffix -ose (2).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for lactose

lactose

[ lăktōs′ ]

n.

A disaccharide in milk that hydrolyzes to yield glucose and galactose.milk sugar
A white crystalline substance obtained from whey and used in infant foods and in pharmaceuticals as a diluent and excipient.milk sugar

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for lactose

lactose

[ lăktōs′ ]

A white crystalline disaccharide consisting of a glucose and a galactose molecule, found in milk and used in the manufacture of various other foods. Chemical formula: C12H22O11.
The inability to digest lactose properly is called lactose intolerance. It is caused by a deficiency of the enzyme lactase and marked by abdominal cramping and other symptoms after ingesting lactose.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.