My daughter calls her partner a business partner. They are involved in transportation. As far as I know, they just deliver shipments running in tandem. (motorhomes, delivery trucks, etc) If they are partnering on the sly, that's their business. They even share a house with his wife (disabled due to several strokes) and his daughter (Down's Syndrome) and her three girls. If someone uses the term partner, I'm not afraid to ask them what type of partner.