[ahr-guh
l] 
| a crude tartar, produced as a by-product in casks by the fermentation of wine grapes, used as a mordant in dyeing, in the manufacture of tartaric acid, and in fertilizers. |
| ar·gol (är'gôl') n. Crude potassium bitartrate, a by-product of winemaking. [Middle English argoile, from Anglo-Norman argoil, ultimately from Latin argilla, clay; see argil.] |