Define Nibble, Bit and Byte?

Nibble:
 In computers and digital technology, a nibble is four binary digits or half of an eight bit byte. A nibble can be conveniently represented by one hexadecimal digit.

Bit:
 A bit (short for binary digit) is the smallest unit of data in a computer. A bit has a Single binary value, either 0 or 1. Although computers usually provide instructions that can test and manipulate bits, they generally are designed to store data and execute instructions in bit multiples called bytes.

Byte:
 In most computer systems, a byte is a unit of data that is eight binary digits long. A byte is the unit most computers use to represent a character such as a letter, number, or typographic symbol (for example, "g", "5", or "?"). A byte can also hold a string of bits that need to be used in some larger unit for application purposes.