What does it mean when you say apple cider vinegar with the mother?

The mother is the dark, cloudy substance in the ACV formed from naturally occurring pectin and apple residues – it appears as molecules of protein connected in strand-like chains. The presence of the mother shows that the best part of the apple has not been destroyed. Vinegars containing the mother contain enzymes and minerals that other vinegars may not contain due to over processing, filtration, and overheating.