What is difference between a Basilica and a Cathedral?

What are the four major basilicas?

A cathedral is the “cathedra” (chair) of the bishop of a diocese. The reference is to the chair or seat of apostolic authority in that place. It is therefore the principle church in a diocese.  A basilica is a church honored by the pope for some notable reason.

The Holy Father can designate a church as a basilica based on the church’s history or architecture. Once a church is named a basilica, this is a permanent title. 

A basilica may or may not be the cathedral for the diocese.