open shop noun 1verb 1forms 4 noun1 •A place of employment in which employment is in no way contingent on membership in a union, though a union may be the exclusive bargaining agent of the employees. verb1 •(US, India) To begin work or operations.Rosenman left Sandollar to run Brillstein-Grey’s movie division for two years. He then opened shop as an indie producer, developing such films as the Beacon Communications comedy “Family Man,”. — 1999 formsopened shop · opening shop · opens shop · open shops