It's a land area that channels rainfall and snowmelt to creeks, streams, and rivers, and eventually to outflow points such as reservoirs, bays, and the ocean. It is important to know because anything you spill or litter in that river basin will one day end up in the outflow point.
Lentic-Slow moving, still aquatic systems. IE swamps, marshes, ponds, etc…
Lotic- Swift moving aquatic ecosystems like rivers and streams