A byte is the fundamental unit of data storage in computer systems, typically defined as a sequence of 8 bits. A byte consists of 8 bits, which is the smallest addressable unit of memory for most modern computer architectures. A bit is the smallest unit of data, representing a binary value (0 or 1). A group of 4 bits is called a nibble. Larger units include words, which consist of varying numbers of bytes depending on the computer architecture (e.g., 2 bytes for a 16-bit word, 4 bytes for a 32-bit word, 8 bytes for a 64-bit word).