Source : Webster's Revised Unabridged Dictionary (1913)

Whitsuntide \Whit"sun*tide`\, n. [Whitsunday + tide.]
   The week commencing with Whitsunday, esp. the first three
   days -- Whitsunday, Whitsun Monday, and Whitsun Tuesday; the
   time of Pentecost. --R. of Gloucester.

Source : WordNet®

Whitsuntide
     n : Christian holiday; the week beginning on Whitsunday
         (especially the first 3 days) [syn: {Whitsun}, {Whitweek}]