Main Entry:
Eas·ter
Pronunciation: 'E-st&r
Function:
noun
Etymology: Middle English
estre, from Old English
Eastre; akin to Old High German
Ostarun (plural) Easter, Old English
East east
: a feast that commemorates Christ's resurrection and is observed with variations of date due to different calendars on the first Sunday after the paschal full moon
[Easter table]
Source:
Merriam-Webster Dictionary
More information also in:
http://en.wikipedia.org/wiki/Easter