The prefix "tera" is a unit of measurement in the metric system that denotes a factor of 10^12 or 1,000,000,000,000. It is commonly used in fields such as computing and data storage to describe large quantities, such as terabyte (TB), which equals 1 trillion bytes. In scientific contexts, "tera" is part of the International System of Units (SI) and helps simplify the expression of large numbers. For example, terahertz (THz) is a frequency unit equal to 10^12 hertz, often used in telecommunications and spectroscopy.