from The Century Dictionary and Cyclopedia
- n. See mother, 2.
Sorry, no etymologies found.
The jelly-like substance mother-of-vinegar is in fact a mass of cells of the bacterium Acetobacter aceti var. xylinum.
You will not produce vinegar if you add mother-of-vinegar to water, but you will if you add it to an alcoholic liquid such as beer or wine and then leave it exposed to the air for a while.
Nowadays, commercial vinegar is pasteurised before bottling, so you tend not to see mother-of-vinegar develop.