sed-, sedat-, -sid, -sess +

1. To replace in power, authority, effectiveness, acceptance, use, etc., as by another person or thing.
2. To set aside or to cause to be set aside as void, useless, or obsolete, usually in favor of something else; to make obsolete: "They superseded the old car with a new one."
3. To succeed to the position, function, office, etc., of; to supplant.
4. To cause to be set aside; especially, to displace someone or something as inferior or antiquated.

Literally, "to sit over or above" or "to sit on top of" something.

Taking the place of (something); especially, because it is considered old or not good enough: "No sooner do you buy a computer than they bring out a new one that is superseding it."

The act of replacing one person or thing by another one; especially, one held to be superior.

1. To cease, or to bring something to an end.
2. Etymology: from Anglo-French surseser; from Old French sursis, past participle of surseoir, "to refrain, to delay"; from Latin supersedere, "to sit on top of, to stay clear of, to abstain from, to forbear, to refrain from"; from super, "above" + sedere, "to sit".