Because there are two parts of an address and an item may or may not be in a current segment, there are two ways to specify the address of a data item.
A NEAR ADDRESS is an offset without specifying a selector. This is a very efficient way to address data because the overhead of loading a selector register and fetching the descriptor is avoided. The selector to use is implied, and is normally already loaded.
A FAR ADDRESS contains both a selector and an offset in protect mode. This is slower and more cumbersome because both address components must be specified as well as causing the overhead of altering a selector register. When a far address is displayed from storage (as two words), the offset will be seen in the left word, and the segment or selector in the right word.
A FAR ADDRESS contains a segment and an offset in real or V86 mode. The overhead is not so bad as in protect mode, because there are no descriptors to fetch when a segment register is loaded.