Alkali is another word wearing the Arabic definite article. The source is al-qaliy, "the ashes" or "burnt ashes," from a verb meaning "to roast in a pan" — specifically the ashes of saltwort, a plant that grows in alkaline soils and is correspondingly rich in soda. English took it in the late 1300s through Medieval Latin, meaning soda ash, exactly the substance the Arabic described.
From there it widened in the ordinary way: first to similar substances, natural or manufactured, and then in 1813 to the modern chemical sense, one half of the acid-and-alkali pairing. The spelling has barely moved in six hundred years, which is unusual — most words that old have been respelled at least once by someone trying to make them look Latin.
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. The modern chemistry sense is from 1813. also from late 14c.
alkali came in through Later and wider borrowings, and its spelling follows that family's conventions.
What gives it away on the page
| al- fused to the front of the noun | Arabic, usually via Spanish or Latin — al is the article, stuck on permanently.alcohol, algebra, algorithm, alkali, almanac, admiral |
Later and wider borrowings in the spelling guide · guess another word's family