Symbols are used in a schematic capture that represents the logical design of a PCB. A schematic capture has instances of symbols interconnected by “nets”. A “net” is essentially an electrical node. Note that a “net” connects from a pin to another pin, and those pins can be on the same symbol. Furthermore, a net can also connect any number of pins.
A “net” is typically represented by a line that connects to at least one pin. A net that connects two pins obviously specifies that the two pins share the same electrical node. However, a “net” can also be specified by name. This means that multiple pins can each connect to a line that goes no where. If all the “dangling” lines share the same name, they still logically represent a single node. This means that all pins connected to lines that are identically named are all connected logically.
Note that it is okay for lines in a schematic capture to cross path. This is because a schematic diagram is merely representing how pins should be logically connected.