[ lak-teys, -teyz ]
/ ˈlæk teɪs, -ˌteɪz /

noun Biochemistry.

an enzyme capable of hydrolyzing lactose into glucose and galactose.

Origin of lactase

First recorded in 1890–95; lact- + -ase Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for lactase


/ (ˈlækteɪs, -teɪz) /


any of a group of enzymes that hydrolyse lactose to glucose and galactose

Word Origin for lactase

C20: from lacto- + -ase
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

Medicine definitions for lactase


[ lăktās′ ]


A galactosidase occurring in the intestine that catalyzes the hydrolysis of lactose into glucose and galactose.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for lactase


[ lăktās′ ]

An enzyme that is found in the small intestine, liver, and kidneys of mammals and catalyzes the breakdown of lactose into galactose and glucose.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.