Prefix (not productive).
The Arabic definite article al, forming an essential element of many words of Romance (esp. Spanish, and Portuguese) origin adopted in English, as alcohol, alcove, algebra, alkali.
The many and varied influences of the English language always fascinate me, and are an inextricable part of the beauty and richness of the language. I also got to discover a supposed transliteration of Lexicolatry into Arabic's beautiful script. Score!