ˈēstə(r)ˌtīd noun
also easter time
Usage: usually capitalized E
Etymology: Eastertide from Middle English estertide Easter season, from Old English ēastertīd, from ēaster Easter + tīd time; Easter time from Middle English ester time period from Easter to Whitsunday, from ester Easter + time — more at tide
: a period extending from Easter to Ascension Day, to Whitsunday, or to Trinity Sunday