Nibble
（重定向自Quadbit）
In computing, a nibble (often nybble or nyble to match the vowels of byte) is a four-bit aggregation, or half an octet. It is also known as half-byte or tetrade. In a networking or telecommunication context, the nibble is often called a semi-octet, quadbit, or quartet. A nibble has sixteen (2) possible values. A nibble can be represented by a single hexadecimal digit and called a hex digit.