The Collaborative International Dictionary of English v.0.48:

Alas \A*las"\, interj. [OE. alas, allas, OF. alas, F. h['e]las;
   a interj. (L. ah.) + las wretched (that I am), L. lassus
   weary, akin to E. late. See Late.]
   An exclamation expressive of sorrow, pity, or apprehension of
   evil; -- in old writers, sometimes followed by day or white;
   alas the day, like alack a day, or alas the white.
   [1913 Webster]

WordNet (r) 3.0 (2006):

alas
    adv 1: by bad luck; "unfortunately it rained all day"; "alas, I
           cannot stay" [syn: unfortunately, unluckily,
           regrettably, alas] [ant: as luck would have it,
           fortuitously, fortunately, luckily]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ALAS
       Asociacion Latinoamericana de Seguridad (org.)