The Collaborative International Dictionary of English v.0.48:

Typo \Ty"po\, n. [An abbreviation of typographer.]
   A compositor. [Colloq.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Typo \Ty"po\, n. [An abbreviation of typographical error.]
   a typographical error; an error in typing, printing, etc.
   [Colloq.]
   [PJC]

WordNet (r) 3.0 (2006):

typo
    n 1: a mistake in printed matter resulting from mechanical
         failures of some kind [syn: misprint, erratum,
         typographical error, typo, literal error, literal]

The Free On-line Dictionary of Computing (19 January 2023):

typographical error
typo

   (typo) An error while inputting text via keyboard, made
   despite the fact that the user knows exactly what to type in.
   This usually results from the operator's inexperience at
   keyboarding, rushing, not paying attention, or carelessness.

   Compare: mouso, thinko.

   (1996-04-20)