lacto-

1. a combining form meaning “milk,” used in the formation of compound words (lactometer); specialized in chemical terminology to mean “lactate,” or “lactic acid.”

combining form

1. indicating milklactobacillus

before vowels, lac-, word-forming element meaning “milk,” from Latin lac (genitive lactis) “milk,” from PIE root *glakt- (see lactation). pref.

1. Milk:lactoglobulin.
2. Lactose:lactase.
3. Lactic acid:lactate.