The Collaborative International Dictionary of English v.0.48:

Bliss \Bliss\ (bl[i^]s), n.; pl. Blisses (bl[i^]s"[e^]z). [OE.
   blis, blisse, AS. blis, bl[imac][eth]s, fr. bl[imac][eth]e
   blithe. See Blithe.]
   Orig., blithesomeness; gladness; now, the highest degree of
   happiness; blessedness; exalted felicity; heavenly joy.
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         An then at last our bliss
         Full and perfect is.                     --Milton.
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   Syn: Blessedness; felicity; beatitude; happiness; joy;
        enjoyment. See Happiness.
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