supersede: [15] Etymologically, to supersede something is to ‘sit above’ it, hence to ‘be above’ it or ‘desist’ from doing it. The word comes via Old French superseder from Latin supersedēre ‘desist from’, a compound verb formed from the prefix super- ‘above’ and sedēre ‘sit’ (source of English sedentary, session, etc).
It carried the sense ‘desist from’ with it into English (‘I could not see, but your both majesties must supersede and give place to your ardent appetites, in concluding of the said marriage’, State Papers of Henry VIII 1527), but this gradually evolved via ‘set aside’ to ‘take the place of something set aside’. The word is frequently spelled supercede, as if it came from Latin cēdere ‘go’, and there are long-standing historical precedents for this, going back via Old French superceder to medieval Latin supercēdere. => sedentary, session
supersede (v.)
mid-15c., Scottish, "postpone, defer," from Middle French superceder "desist, delay, defer," from Latin supersedere literally "sit on top of;" also, with ablative, "stay clear of, abstain from, forbear, refrain from," from super "above" (see super-) + sedere "to sit" (see sedentary). Meaning "displace, replace" first recorded 1640s. Related: Superseded; superseding.
