system (n.)

1610s, "the whole creation, the universe," from Late Latin systema "an arrangement, system," from Greek systēma "organized whole, a whole compounded of parts," from stem of synistanai "to place together, organize, form in order," from syn- "together" (see syn-) + root of histanai "cause to stand" (from PIE root *sta- "to stand, make or be firm"). The notion is "a combination or assemblage of parts or things forming or adjusted as a regular and connected whole."

The meaning "set of correlated principles, facts, ideas, etc." is attested by 1630s. The meaning "animal body as an organized whole, sum of the vital processes in an organism" is recorded from 1680s; hence the figurative phrase get (something) out of (one's) system, attested by 1900.

By 1680s as "group of bodies moving together in space, bound by laws of dynamics," as the sun and its planets. The computer sense of "group of related programs" is recorded from 1963. All systems go (1962) is from U.S. space program. The system "prevailing social order" is from 1806.