What is "radical vinegar"

Vinegar \Vin"e*gar\, n. [OE. vinegre, F. vinaigre; vin wine (L. vinum) + aigre sour. See Wine, and Eager, a.]

1. A sour liquid used as a condiment, or as a preservative, and obtained by the spontaneous (acetous) fermentation, or by the artificial oxidation, of wine, cider, beer, or the like.

   Note: The characteristic sourness of vinegar is due to acetic acid, of which it contains from three to five per cent. Wine vinegar contains also tartaric acid, citric acid, etc.

2. Hence, anything sour; -- used also metaphorically.

   Here's the challenge: . . . I warrant there's vinegar and pepper in't.
   --Shak.

   Aromatic vinegar, strong acetic acid highly flavored with aromatic substances.

   Mother of vinegar. See 4th Mother.

   Radical vinegar, acetic acid.

   Thieves' vinegar. See under Thief.

   Vinegar eel (Zo["o]l.), a minute nematode worm ( Leptodera oxophila, or Anguillula acetiglutinis), commonly found in great numbers in vinegar, sour paste, and other fermenting vegetable substances; -- called also vinegar worm.

   Vinegar lamp (Chem.), a fanciful name of an apparatus designed to oxidize alcohol to acetic acid by means of platinum.

   Vinegar plant. See 4th Mother.

   Vinegar tree (Bot.), the stag-horn sumac ( Rhus typhina), whose acid berries have been used to intensify the sourness of vinegar.

   Wood vinegar. See under Wood.