Source : Webster's Revised Unabridged Dictionary (1913)

Al- \Al-\ A prefix.
   (a) [AS. eal.] All; wholly; completely; as, almighty, almost.
   (b) [L. ad.] To; at; on; -- in OF. shortened to a-. See
       {Ad-}.
   (c) The Arabic definite article answering to the English the;
       as, Alkoran, the Koran or the Book; alchemy, the
       chemistry.