Definition:
The word "extraterrestrial" is an adjective that describes anything that comes from outside of Earth or its atmosphere. It can also be used as a noun to refer to a being or life form that is believed to exist outside of our planet.
As an Adjective: Use "extraterrestrial" to describe objects, phenomena, or concepts that are not from Earth.
As a Noun: Use "extraterrestrial" to refer to beings or life forms that are thought to exist in outer space.
In scientific discussions, "extraterrestrial" can refer to various topics, such as extraterrestrial biology (the study of life forms outside Earth), extraterrestrial intelligence (the search for intelligent life in the universe), and extraterrestrial geology (the study of the physical characteristics of celestial bodies).
While "extraterrestrial" primarily refers to life or objects from outside Earth, it can also be used in a broader context to discuss anything that is foreign or not of this world metaphorically.
While there are no specific idioms or phrasal verbs directly related to "extraterrestrial," you may hear phrases like "out of this world" to describe something extraordinary, which can be loosely connected to the concept of extraterrestrial life or phenomena.
In summary, "extraterrestrial" is a versatile word used to describe anything from beyond Earth, including the possibility of life forms that exist in outer space.