To throw or propel with force; hurl: launch a spear. To set or thrust (a self-propelled craft or projectile) in motion: launch a rocket; launch a torpedo. Nautical To put (a boat) into the water in readiness for use. To set going; initiate: launch a career; launch a business venture. To introduce to the public or to a market: launched the new perfume with prime-time commercials on the major networks. To give (someone) a start, as in a career or vocation. To begin a new venture or phase; embark: launch forth on a dangerous mission; launched out on her own after college. To enter enthusiastically into something; plunge: launched into a description of the movie. The act of launching. A large ship's boat. A large, open motorboat.