noun - EF is an acronym commonly used for 'emission factor', a coefficient that quantifies the emissions or removals of a gas per unit activity.

noun - EF also stands for 'education first', an international education company that offers study abroad, language learning, cultural exchange and academic programs.

noun - In music, EF could refer to 'E Flat', a musical note.

noun - In health, EF is often used for 'ejection fraction', a measure of the percent of blood leaving the heart each time it contracts.

noun - EF is also a measure used in meteorology referring to 'enhanced Fujita', a scale for rating tornado intensity.