Being
Old English bēon, an irregular and defective verb, whose full conjugation derives from several originally distinct verbs. The forms am and is are from an Indo-European root shared by Latin sum and est . The forms was and were are from an Indo-European root meaning ‘remain’. The forms be and been are from an Indo-European root shared by Latin fui ‘I was’, fio ‘I become’, and Greek phuein ‘bring forth, cause to grow’. The origin of are is uncertain.
wiktionary
Originated 1250–1300 from Middle Englishbeing; see be + -ing.
etymonline
being (n.)
c. 1300, "existence," in its most comprehensive sense, "condition, state, circumstances; presence, fact of existing," early 14c., existence," from be + -ing. Sense of "that which physically exists, a person or thing" (as in human being) is from late 14c.
