-ing (?).
1. [For OE. -and, -end, -ind, AS. -ende; akin to Goth. -and-, L. -ant-, -ent-, Gr. .]
A suffix used to from present participles; as, singing, playing.
2. [OE. -ing, AS. -ing, -ung.]
A suffix used to form nouns from verbs, and signifying the act of; the result of the act; as, riding, dying, feeling. It has also a secondary collective force; as, shipping, clothing.
⇒ The Old English ending of the present participle and verbal noun became confused, both becoming -ing.
3. [AS. -ing.]
A suffix formerly used to form diminutives; as, lording, farthing.
© Webster 1913.