The American Heritage® Dictionary of the English Language, 4th Edition
n. Any of various rod-shaped, nonmotile aerobic bacteria of the genus Lactobacillus that ferment lactic acid from sugars and are the causative agents in the souring of milk.
n. Any of many rod-shaped, nonmotile, aerobic bacteria, of the genus Lactobacillus, that ferment sugars to form lactic acid
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a Gram-positive rod-shaped bacterium that produces lactic acid (especially in milk)
Word Usage
"Next she tracked down and begged for a culture of the yeast strain he suggested called lactobacillus, finally obtaining it from a fellow brewery in Bend."