The Random House Webster's Unabridged Dictionary
) defines carpool as an arrangement
among a group of automobile
owners by which each owner
in turn drives
the others or their children to and from a designated place
While this is true, it is not completely accurate. For instance, my husband is part of a carpool with a friend to their work, as they both work for the same company and it would be foolish for them to drive separately. Where it breaks down is the fact that my husband never drives. There is no taking turns in this carpool. The friend drives always, and my husband buys him lunch on Fridays.
Another time when a carpool does not fit the Webster definition is when a person has a passenger for the sole purpose of being able to legally utilize the carpool lane. My mother used to take me and/or my brother with her when she would visit my aunt so that she could use the carpool lane and cut down on the time it took to get to and from my aunt's house. I personally don't consider this to be a proper use of the carpool lane, although it is a common one.