The term "extra terrestrial" refers to beings or objects that are from outside of Earth. There are many synonyms for this word, such as "alien," "extraterrestrial," "ET," "outer space," "cosmic," and "astronomical." Some of these synonyms are more commonly used in popular culture, such as "alien" and "ET," while others are more scientific in nature, such as "cosmic" and "astronomical." Regardless of which synonym is used, they all refer to the same concept of things that exist beyond Earth. Whether they are real beings or simply imagined ones, the concept of extra terrestrials has captivated the imagination of people for centuries.