1610s, "the whole creation, the universe," from Late Latin systema "an arrangement, system," from Greek systema "organized whole, body," from syn- "together" (see syn-) + root of histanai "cause to stand" from PIE root *sta- "to stand" (see stet). Meaning "set of correlated principles, facts, ideas, etc." first recorded 1630s. Meaning "animal body as an organized whole, sum of the vital processes in an organism" is recorded from 1680s; hence figurative phrase to get (something) out of one's system (1900). Computer sense of "group of related programs" is recorded from 1963. All systems go (1962) is from U.S. space program.
system sys·tem (sĭs'təm)
A group of interacting, interrelated, or interdependent elements forming a complex whole.
An organism or body considered as a whole, especially with regard to its vital processes or functions.
A group of physiologically or anatomically complementary organs or parts.