Dictionary.com

lactose

[ lak-tohs ]
/ ˈlæk toʊs /
Save This Word!

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.
QUIZ
WILL YOU SAIL OR STUMBLE ON THESE GRAMMAR QUESTIONS?
Smoothly step over to these common grammar mistakes that trip many people up. Good luck!
Question 1 of 7
Fill in the blank: I can’t figure out _____ gave me this gift.
Also called milk sugar, sugar of milk.

Origin of lactose

First recorded in 1855–60; lact- + -ose2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use lactose in a sentence

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

Scientific 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.
FEEDBACK