Both bus and coach are used for carrying passengers to a place, so the two terms are often used interchangeably. However, there is difference between them in terms of service, comfort and price. Buses usually have a schedule according to which they stop frequently at given stops. Coaches make stops too but less frequently. They refer to more luxurious form of bus and they usually cover longer distance, from one city to another or even from one country to another. Because of this, coaches tend to have toilets, DVD players, and air conditioning and so on in them. They have also have bigger and more comfortable seats. So a bus route is usually a local service, and you can not book a ticket in advance, not like for a coach. From another point of view, coach can refer to the cart or chariot on the one hand, on the other hand, it can also mean the railway carriage. Thirdly, it also refers to a person who gives private lessons but also a person who trains athletes.
