'Stet' definitions:

Definition of 'stet'

verb

Printing: cancel, as of a correction or deletion

verb

Printing: direct that a matter marked for omission or correction is to be retained (used in the imperative)

From: GCIDE

Stet \Stet\ (st[e^]t), L., subj. 3d pers. sing. of stare to stand, remain. [See Stand.] (Print.) Let it stand; -- a word used by proof readers to signify that something once erased, or marked for omission, is to remain. [1913 Webster]

From: GCIDE

Stet \Stet\, v. t. [imp. & p. p. Stetted; p. pr. & vb. n. Stetting.] (Print.) To cause or direct to remain after having been marked for omission; to mark with the word stet, or with a series of dots below or beside the matter; as, the proof reader stetted a deled footnote. [1913 Webster]