Also brethren something, such as a corporation or institution, that is regarded as a member point a class. Choose between business or home office solutions and get the quality product you need. Relies on corporate contributions or advertising to survive runs the risk up becoming virtually indistinguishable from its commercial brethren. Brother definition, a male offspring having both parents in common with another offspring. Whether you need a major, scalable solution for your multinational corporation, a printer for your home office, or a sewing machine for your new hobby, brother has what you need.