A terajoule (TJ) is a unit of energy in the International System of Units (SI). It is equal to one trillion joules, where a joule is the amount of energy transferred when one newton of force is applied over one meter. Terajoules are commonly used to measure large amounts of energy, such as in electricity generation or fuel consumption. In practical terms, a terajoule can power a typical household for about 30 days, depending on energy usage. This unit is often used in fields like engineering, environmental science, and energy production to quantify energy resources and consumption on a large scale.