(1) Abbreviation for the term extraterrestrial
(2) A symbol for exatesla
(3) (pathology) Abbreviation for essential thrombocythemia
(4) Abbreviation for electron tomography
(5) Abbreviation for electron transfer
(6) Abbreviation for ethyl group
(7) Abbreviation for evapotranspiration
ET is used in various unrelated fields. For instance, it may pertain to the symbol used for exatesla, which is an SI unit of magnetic flux density equal to 1018 teslas; one tesla is equal to 1 weber per square meter (m2). Perhaps, the most popular notion of ET is in the field of astrobiology, which is the field of biology concerned in the study of life on space and earth. In this regard, ET is the abbreviated form of the term extraterrestrial, which pertains to space or that outside the earth's atmosphere. Extraterrestrial life is a controversial topic because no consensus is reached till now if there is truly an intelligent life outside the earth or if there is none. No concrete evidence has been presented to this date. Despite of the lack of proof through years of research, probe on possible extraterrestrial intelligent living beings continues.