Supersede

Fascinatingly, by far the most common error in creating a forged supersede is to spell it supercede.

Superseding a message is effectively equivalent to posting a cancel followed by a new message, but is accomplished in a single message. Like cancels, many servers do not honour supersedes due to large-scale abuse.

Su`per*sede" (?), v. t. [imp. & p. p. Superseded (?); p. pr. & vb. n. Superseding.] [L. supersedere, supersessum, to sit above, be superior to, forbear, omit; super above + sedere to sit: cf. F. supers'eder. See Sit, and cf. Surcease.]

1.

To come, or be placed, in the room of; to replace.

2.

To displace, or set aside, and put another in place of; as, to supersede an officer.

3.

To make void, inefficacious, or useless, by superior power, or by coming in the place of; to set aside; to render unnecessary; to suspend; to stay.

Nothing is supposed that can supersede the known laws of natural motion. Bentley.

4. OldLaw

To omit; to forbear.

© Webster 1913.