[1] : The Collaborative International Dictionary of English v.0.48

alas \alas"\, interj. oe. alas, allas, of. alas, f. h'elas;
   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
see also:
late 

[2] : WordNet (r) 2.0

alas
     adv : by bad luck; "unfortunately it rained all day"; "alas, i
           cannot stay" syn: unfortunately, unluckily, regrettably
           ant: fortunately, fortunately
see also:
unfortunately unluckily regrettably fortunately 

Alas >> A Words
Alas, definition of term: Alas
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