Webster's Revised Unabridged Dictionary · 1913

Bliss

Bliss (blis) , noun

[Old English blis, blisse, Anglo-Saxon blis, blīes, from blīee blithe. See Blithe.]

Orig., blithesomeness; gladness; now, the highest degree of happiness; blessedness; exalted felicity; heavenly joy.
An then at last our bliss Full and perfect is. — Milton