brainchild /ˈbɹeɪnt͡ʃaɪld/noun 1verb 1forms 4 noun1 •A creation of one's brain; an original idea or innovation of a person or group of people, an organization, etc.The entire project was the brainchild of a small group of visionaries. verb1 •(rare) To think up (an idea or innovation); to come up with.John Law brainchilded the establishment of a national bank to expedite and secure the creation of credit. — 2014 formsbrainchilded · brainchilding · brainchilds · brainchildren