A byte is composed of 8 bits or "on-off" signals. You can think of a byte as being the computer representation for a letter, like "A," a number like "7," or an instruction to multiply two numbers, like "3 * 6." For the purposes of creating a Web site, the number of bytes will measure the size of your site in terms of disk space. For instance, if your Web hosting plan allows you to publish a 2 MB (Megabytes or million bytes) Web site, then essentially it can be made up of 2 million characters or instructions.
Equal to 8 bits, one Byte of data is the standard unit of measure on the Internet. Each Byte represents one character (such as a letter or number). Often you will see terms like KiloByte (KB), which is one thousand Bytes, or MegaByte (2 MB or 2 Megs), one million Bytes, or GigaByte (e.g., 2 GB or 2 Gigs) which is one billion Bytes. Now you may even see the term TeraByte, which represents one trillion Bytes
A group of bits, usually eight, handled as a unit, that stores a piece of information such as a character. Computer memory is measured in bytes; "64K" means a computer has 64 kilobytes (64,000 bytes) or 512,000 bits of memory.