A star topology refers to a central device that each device centrally connects to. It resembles a star because the central device resembles a star with the connected devices radiating from the center.
A mesh topology is where each device connects to every other device. This results in a large fault tolerance as each node is interconnected to every other node but requires more connections as the network grows making it inefficient.
A partial mesh is where only some devices are fully interconnected. A full mesh refers to where every device is fully interconnected.
A design which combines aspects of the star and mesh topologies.