half byte
In many cases, the division of the 8 bits of a byte into two equal halves makes sense, for example, if related but not very information-intensive data is to be processed together.
When a byte is divided into two equal half-sized units, two half-bytes are created. The best-known example of this is the joint representation of two hexadecimal numbers (sedecimal numbers). Half bytes are also used in the EBCDIC code (Extended Binary Coded Decimal Interchange Code). A half-byte is also commonly called a nibble.
If two bits are combined to a group, it is called a dibit, if three bits are combined, it is called a tribit and if 8 bits are combined, it is called a byte.