Easter (n.)youdaoicibaDictYouDict
Old English Easterdæg, from Eastre (Northumbrian Eostre), from Proto-Germanic *austron-, "dawn," also the name of a goddess of fertility and spring, perhaps originally of sunrise, whose feast was celebrated at the spring equinox, from *aust- "east, toward the sunrise" (compare east), from PIE *aus- (1) "to shine" (especially of the dawn); see aurora.

Bede says Anglo-Saxon Christians adopted her name and many of the celebratory practices for their Mass of Christ's resurrection. Almost all neighboring languages use a variant of Latin Pascha to name this holiday (see paschal). Easter egg attested by 1825, earlier pace egg (1610s). Easter bunny attested by 1904 in children's lessons; Easter rabbit is by 1888; the paganish customs of Easter seem to have grown popular c. 1900; before that they were limited to German immigrants.
If the children have no garden, they make nests in the wood-shed, barn, or house. They gather colored flowers for the rabbit to eat, that it may lay colored eggs. If there be a garden, the eggs are hidden singly in the green grass, box-wood, or elsewhere. On Easter Sunday morning they whistle for the rabbit, and the children imagine that they see him jump the fence. After church, on Easter Sunday morning, they hunt the eggs, and in the afternoon the boys go out in the meadows and crack eggs or play with them like marbles. Or sometimes children are invited to a neighbor's to hunt eggs. [Phebe Earle Gibbons, "Pennsylvania Dutch," Philadelphia 1882]
-s (1)youdaoicibaDictYouDict
suffix forming almost all Modern English plural nouns, gradually extended in Middle English from Old English -as, the nominative plural and accusative plural ending of certain "strong" masculine nouns (such as dæg "day," nominative/accusative plural dagas "days"). The commonest Germanic declension, traceable back to the original PIE inflection system, it is also the source of the Dutch -s plurals and (by rhotacism) Scandinavian -r plurals (such as Swedish dagar).

Much more uniform today than originally; Old English also had a numerous category of "weak" nouns that formed their plurals in -an, and other strong nouns that formed plurals with -u. Quirk and Wrenn, in their Old English grammar, estimate that 45 percent of the nouns a student will encounter will be masculine, nearly four-fifths of them with genitive singular -es and nominative/accusative plural in -as. Less than half, but still the largest chunk.

The triumphs of -'s possessives and -s plurals represent common patterns in language: using only a handful of suffixes to do many jobs (such as -ing), and the most common variant squeezing out the competition. To further muddy the waters, it's been extended in slang since 1936 to singulars (such as ducks, sweets, babes) as an affectionate or diminutive suffix.

Old English single-syllable collectives (sheep, folk) as well as weights, measures, and units of time did not use -s. The use of it in these cases began in Middle English, but the older custom is preserved in many traditional dialects (ten pound of butter; more than seven year ago; etc.).