The Collaborative International Dictionary of English v.0.48:

Erector \E*rec"tor\, n.
   1. One who, or that which, erects.
      [1913 Webster]

   2. (Anat.) A muscle which raises any part.
      [1913 Webster]

   3. (Physics) An attachment to a microscope, telescope, or
      other optical instrument, for making the image erect
      instead of inverted.
      [1913 Webster]