1. In Spain the saltwort plant was burned, producing an alkaline ash called barilla.

2. From Dutch alkali, from French Alcali, ultimately from Arabic اَلْقِلْي‎ (al-qily, “ alkali, ashes of the saltwort ”), related to قَلَى‎ (qalā, “ to roast in a pan, fry ”)

3. Alkali (n.) late 14c., "soda ash," from Medieval Latin Alkali, from Arabic al-qaliy "the ashes, burnt ashes" (of saltwort, which abounds in soda due to growing in Alkaline soils), from qala "to roast in a pan." Later extended to similar substances, natural or manufactured