a slip of the pen

slip of the pen

An unintentional mistake in one's writing, such as incorrect spelling, word choice, or meaning. Whoops, I meant to tell my mother that she was welcome to call over next Monday, but I actually wrote "next month" instead. Oh well, she'll understand that it was just a slip of the pen. Now take your time while writing these test essays—you don't want a few slips of the pen to be the reason you get a lower grade!
See also: of, pen, slip
Farlex Dictionary of Idioms.

a slip of the pen

A slip of the pen is something you wrote by mistake. The translator dated his letter `Plymouth 1 June 1618'. This is wrong, and probably a slip of the pen for 11 June.
See also: of, pen, slip
Collins COBUILD Idioms Dictionary, 3rd ed.

a slip of the ˈtongue/ˈpen

a small mistake when speaking or writing: Did I say North Street? Sorry, that was a slip of the tongue — I meant South Street.
See also: of, pen, slip, tongue
Farlex Partner Idioms Dictionary
See also:
  • a slip of the tongue/pen
  • slip of the pen
  • slip of the lip
  • eat (one's) shirt
  • I tell a lie
  • suite
  • tout de suite
  • tout suite
  • garbage in, garbage out
  • two whoops and a holler
References in periodicals archive
LUCKY punter Terry O'Neil won pounds 32,000 after backing the wrong horse with a slip of the pen on his betting slip.
Editor: Indeed, this was a slip of the pen. It should have been National Catholic Reporter.