The glossary below contains many of the terms you will find in common use throughout our website. Please refer to this list to find definitions of terms and answers to other Internet security-related questions.


A measure of memory or storage. A megabyte is approximately 1,000,000 bytes (technically, 2 to the 20th power, or 1,048,576 bytes). Also MB, Mbyte, mbyte, and K-byte.