In computing, a hextet is a sixteen-bit aggregation, or four nibbles. As a nibble typically is notated in hexadecimal format, a hextet consists of 4 hexadecimal digits. A hextet is the unofficial name for each of the 8 blocks in an IPv6 network address.
History
The exact term for 16 bits should be hexadectet, directly related to the term octet. Because it is harder to pronounce, the short form "hextet" is used. However, following "octet", "hextet" would more properly describe a 6 bit aggregation.
An expired Internet Draft explored various alternatives for hextet such as quibble, short for "quad nibble":
Although the word hextet originates from an expired Internet Draft, and is not officialised in the IETF documents, the word is used in technical literature on IPv6 published after the Internet Draft. Official IETF documents simply refer to them as "pieces", though this is probably intended to remain non-committal on a term.
Cisco sources generally use the term quartet as does IPv6.com, a reference either to the four digit grouping or to the fact that it represents four nibbles; however, this term is also used by some to refer to a four-bit aggregation (see nibble).