Nibble

Sometimes spelled nybble, a nibble is half a byte. Being four bits, there are sixteen possible values. A nibble is evenly representable by a hexadecimal number. A full byte is evenly representable by two hexadecimal numbers, therefore it is a common way to display bytes of information as two hexadecimal nibbles.

There is also the 'Nibbles game' very fun, very old and very famous; today present in almost the cell phones.