In general, to broadcast is to cast or throw forth something in all directions at the same time. A radio or television broadcast is a program that is transmitted over airwaves for public reception by anyone with a receiver tuned to the right signal.
Using broadcast signals transferred to and from communication satellites, satellite broadcasting is a method of distributing content. Satellite dishes, also known as parabolic antennae, are used to receive the broadcast signals. The signals are then conditionally sent through a low-noise block converter.
A webcast is a media presentation that is broadcast over the Internet utilizing streaming media technologies to reach several listeners and watchers at once. A webcast may be viewed live or after the fact. Webcasting is essentially "broadcasting" via the Internet.