In OE. itself was developed the notion of a completed action or process or the result of this, (whence) habit, art, e.g. blētsung, -ing blessing, benediction, gaderung collection, assembly, leornung learning, study; transference to concrete or material accompaniment or product of a process followed, as in bedding bed-clothes, eardung dwelling, offrung -sacrifice. The existence of a parallel sb. of the same form as the vb. (as in clothes/clothing) has led to the creation of -ing-forms without a corresponding verb, as coping, scaffolding, tubing. Individualized use, with consequent pluralization, began early and became prominent in later periods, e.g. a long sitting, three sittings; a bad beginning but a happy ending; an outing, frequent outings. In some plurals the concr. use appears almost exclusively, e.g. earnings, leavings, trappings. EVENING and MORNING are special formations.
B. The outstanding development of the verbal sb. in -ing is its use as a gerund, so that it may be qualified by adjs. and advs. and may take an object and a predicative noun or adj., e.g. the habit of rising early, engaged in building a house; (with an object and predicated pp.) after having written a letter. The germ of such constructions may be seen in such OE. comps. as āðswerung swearing of oaths, feaxfallung falling-out of hair, mynsterclǣnsung purification of a church, where the first el. is a sb. in subjective, objective, or adverbial relation, or an adverb, and in such constructions as oftr̄ǣdliċe rædinga hāligra bōca frequent readings of holy books (objective genitive). The attrib. use of the gerund, as in breeding place, dancing lesson, living room, thanksgiving day, winning post, has its antecedent models in the earliest periods; e.g. OE. cenningstōw birthplace, huntingspere hunting-spear, ME. gretinng word salutation.
"-ing." The Concise Oxford Dictionary of English Etymology. . Encyclopedia.com. (September 19, 2018). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/ing-0
"-ing." The Concise Oxford Dictionary of English Etymology. . Retrieved September 19, 2018 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/ing-0