What is the meaning of the word "bus"?

Definitions:

a car that is old and unreliable noun
- the fenders had fallen off that old bus
an electrical conductor that makes a common connection between several circuits noun
- the busbar in this computer can transmit data either way between any two components of the system
to remove used dishes from the table in restaurants verb
- I bussed the tables before taking my break.
to ride in a bus verb
- The students bussed to school.
to send or move around by bus verb
- The children were bussed to school.