Definition - What does Nibble mean?
A “nibble” (also spelled “nybble”) in IT parlance is a four-bit data set equal to half of a byte. This is also sometimes called a quadbit, a half-byte, a tetrade or semi-octet.
Techopedia explains Nibble
As a unit of data representation, nibbles have been used in some types of processors and microcontrollers. One example is where nibbles can be used to store individual digits of large integers stored in a "packed decimal format" in IBM systems. The nibble was also prominent in the design of Apple II disk data management.
Within the system of groups of nibbles that are representing hexadecimal values or other units of information, engineers might use the terms “high nibble” and “low nibble” to talk about the sequence of storage within a given byte. They may also talk about “big-endian” or “little-endian” systems for storing sequences of nibbles.