Where does the word “alkali” come from and What does it mean?

Like our mathematics, we owe much of the early study of chemistry to Arabic scholars of the so-called Dark Ages.

Thus the word alkali is but a transliteration of the Arabic al-qaliy, which means “the ashes of saltwort.” Saltwort is a marine plant used in the production of sodium carbonate, formerly called soda ash.

As chemists learned that other salts than sodium carbonate possessed some properties in common with it, alkali became a term common for all.