An omission is any segment of text that a copyist does not reproduce in the copied text, but that is present in the exemplar. In the process of collating and editing the term omission is a relative one which only indicates that a segment of text which is present in the base-text is lacking in some witness(es), without making a judgement whether the omission is secondary or not. One may distinguish omissions intentionally introduced by the scribe from unintentional ones.
Cf. types of errors, addition, haplography, and lacuna.
– Havet, Louis. 1911. Manuel de critique verbale appliquée aux textes latins. Paris: Hachette.