from The American Heritage® Dictionary of the English Language, 4th Edition
- suffix Used to form plural nouns: letters.
- suffix Used to form the third person singular present tense of all regular and most irregular verbs: looks; holds.
- suffix Used to form adverbs: They were caught unawares. He works nights.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- suffix Used to form regular plurals of nouns.
- suffix Used to form many pluralia tantum (nouns that are almost or entirely without singular forms).
- suffix Used to form the third-person singular indicative present tense of verbs.
- suffix used in the formation of certain English adverbs.
- suffix Possessive in business names.
- suffix Diminutive suffix
from the GNU version of the Collaborative International Dictionary of English
- The suffix used to form the plural of most words; as in roads, elfs, sides, accounts.
- The suffix used to form the third person singular indicative of English verbs; as in falls, tells, sends.
- An adverbial suffix; as in towards, needs, always, -- originally the genitive, possesive, ending. See -'s.
Middle English -es, -s, from Old English -es, -as, nominative and accusative pl. suff.
Middle English -es, -s, from Old English (Northumbrian) -es, -as, alteration (perhaps influenced by Old Norse) of -eth, -ath.
Middle English -es, -s, genitive sing. suff., from Old English -es.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Middle English -s, -es, from Old English -as, nominative-accusative plural ending of masculine a-stem (i.e. strong) declension nouns, from Proto-Germanic *-ōs, *-ōz, from Proto-Indo-European *-es, *-oes (plural ending). Most common Old English plural marker (c. 40% of Old English nouns). Cognate with Scots -s (plural ending), West Frisian -s (plural ending), Dutch -s (plural ending), Low German -s (plural ending), Danish -er (plural ending), Swedish -r, -ar, -or (plural ending), Icelandic -ir (plural ending), Gothic (-os, nominative plural ending of a-stem masculine nouns). (Wiktionary)
Middle English -(e)s (third person singular ending of verbs) from Northern Old English (Northumbian dialect) -es, -as (third person singular ending). Replaced historical Old English third person singular ending -(e)þ, -aþ (-eth). Possibly due to Scandinavian influence or related to -es, -as, second-person singular ending of verbs. More at -est (Wiktionary)
From Middle English -es, from Old English -es ("masc-neut genitive ending of most nouns"). More at -'s (Wiktionary)
By dropping the apostrophe in ’s. (Wiktionary)
Shortened form of -sy. (Wiktionary)