word forming element indicating "oneself," also "automatic," from Old English use of self (pron.) in compounds, such as selfbana "suicide," selflice "self-love, pride, vanity, egotism," selfwill "free will." Middle English had self-witte "one's own knowledge and intelligence" (early 15c.).
OED counts 13 such compounds in Old English. Middle English Compendium lists four, counting the self-will group as a whole. It re-emerges as a living word-forming element mid-16c., "probably to a great extent by imitation or reminiscence of Greek compounds in (auto-)," and formed a great many words in the pamphlet disputes of the 17c.
c. 1300, "restrain (someone), control (oneself), behave (in a certain way)," from Old French contein-, tonic stem of contenir, from Latin continere (transitive) "to hold together, enclose," from assimilated form of com "with, together" (see con-) + tenere "to hold" (from PIE root *ten- "to stretch").
From mid-14c. as "to have (something) as a constituent part;" from late 14c. as "have something inside, enclose." Related: Contained; containing; containable.
<a href="https://www.etymonline.com/word/self-contained">Etymology of self-contained by etymonline</a>
Harper, D. (n.d.). Etymology of self-contained. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/self-contained