Units of computing data

Wikipedia also has an article about Units of computing data.

The term byte represents an ordered collection of bits, with each bit representing a binary value of either 0 or 1. In most modern hardware, the defined size of a byte is eight bits, hence by de facto standard there are 2^8 (or 256) distinct values in one byte.An alternate definition of a byte may be given, for example there are 2^16 (or 65536) distinct values in a 16-bit byte, which is more commonly known as a word.

In the Pokémon games, the smallest groups of identifiers can only be read by the console in single 8-bit bytes. This explains for example, the reason why there are 106 identifiers occupying glitch Pokémon recallable via the Ditto Trick in Generation I.