lactase

noun

lac·​tase ˈlak-ˌtās 

-ˌtāz

: an enzyme that hydrolyzes beta-galactosides (such as lactose) and occurs especially in the intestines of young mammals and in yeasts

Examples of lactase in a Sentence

Recent Examples on the Web

The infection damages the gut lining, which leads to a lack of lactase, the enzyme that breaks down lactose. — Adrianna Rodriguez, USA Today, 15 Feb. 2026

In people with lactose intolerance, the body doesn’t produce enough of an enzyme called lactase, which is needed to break down lactose so it can be absorbed. — Jillian Kubala, Health, 14 May 2026

It’s also infused with digestive enzymes—including amylase and lactase—that stave off bloating. — Jenny Berg, Vogue, 25 Nov. 2024

Lactose intolerance, which prevents your small intestine from producing enough lactase, an enzyme needed to digest lactose, a sugar naturally found in dairy products. — Caroline Tien, SELF, 11 Mar. 2026

Word History

Etymology

International Scientific Vocabulary

First Known Use

1891, in the meaning defined above

Rhymes for lactase

• abase
• airspace
• apace
• backspace
• biface
• birthplace
• blackface
• boldface
• bookcase
• braincase
• briefcase
• carcase

Kids Definition

lactase

noun

lac·​tase ˈlak-ˌtās 

: an enzyme that breaks down lactose and related compounds and occurs especially in the intestines of young mammals and in yeasts

Medical Definition

lactase

noun

lac·​tase ˈlak-ˌtās, -ˌtāz 

: an enzyme that hydrolyzes especially lactose to glucose and galactose and occurs especially in the intestines of young mammals and in yeasts