A grave is a more general term for a place where a body is buried often, but not necessarily after a ceremony of some kind.. . A tomb refers to a structure marking a grave or graves which means that a tomb may cover a pit in which a body is buried or it may actually contain a body or bodies. Typically to be a tomb it must have walls and a roof.. . The two terms are frequently used interchangeably or their meanings may be different depending upon the context of their use.