Meaning of ES in English

Pronunciation: ə z, iz after s, z, sh, ch; z after v or a vowel

Function: noun plural suffix

Etymology: Middle English -es, -s ― more at 1 -S

― used to form the plural of most nouns that end in s <glass es >, z <fuzz es >, sh <bush es >, ch <peach es >, or a final y that changes to i <ladi es > and of some nouns ending in f that changes to v <loav es > ― compare 1 -S

Merriam Webster Collegiate English Dictionary.      Merriam Webster - Энциклопедический словарь английского языка.