The Collaborative International Dictionary of English v.0.48:

dolor \do"lor\, n. [OE. dolor, dolur, dolour, F. douleur, L.
   dolor, fr. dolere. See 1st Dole.]
   Pain; grief; distress; anguish. [Written also dolour.]
   [Poetic]
   [1913 Webster]

         Of death and dolor telling sad tidings.  --Spenser.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dolour
    n 1: (poetry) painful grief [syn: dolor, dolour]