-ing (1)youdaoicibaDictYouDict[-ing 词源字典]
suffix attached to verbs to mean their action, result, product, material, etc., from Old English -ing, -ung, from Proto-Germanic *unga (cognates: Old Norse -ing, Dutch -ing, German -ung). Originally used to form nouns from verbs and to denote completed or habitual action. Its use has been greatly expanded in Middle and Modern English.[-ing etymology, -ing origin, 英语词源]
-ing (2)youdaoicibaDictYouDict
suffix used form the present participle of verbs, from Old English -ende (cognates: German -end, Gothic -and, Sanskrit -ant, Greek -on, Latin -ans). It evolved into -ing in 13c.-14c.