sugar of milk

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Lactose.

Wiktionary

1. n. Lactose, a disaccharide found in milk.

GNU Webster's 1913

1. n. The sugar characteristic of milk; a hard white crystalline slightly sweet substance obtained by evaporation of the whey of milk. It is used in pellets and powder as a vehicle for homeopathic medicines, and as an article of diet. See Lactose.
2. n. See under Milk.