- Main Entry:
- lac·tose

- Pronunciation:
-
\ˈlak-ˌtōs, -ˌtōz\
- Function:
- noun
- Etymology:
- International Scientific Vocabulary
- Date:
- 1857
: a disaccharide sugar C12H22O11 that is present in milk and yields glucose and galactose upon hydrolysis and yields especially lactic acid upon fermentation