Definition of "planer"

planer

/ˈpleɪ̯n.əɹ/

adjective
1. comparative form of plane: more plane
noun
plural planers
1. (woodworking) A tool which smooths a surface or makes one surface of a workpiece parallel to the tool's bed.
2. (mechanical engineering) A large machine tool in which the workpiece is traversed linearly (by means of a reciprocating bed) beneath a single-point cutting tool. (Analogous to a shaper but larger and with the workpiece moving instead of the tool.) Planers can generate various shapes, but were most especially used to generate large, accurate flat surfaces. The planer is nowadays obsolescent, having been mostly superseded by large milling machines.
  Quotations
  Besides the usual run of machines, planers, millers, automatics, centre lathes, cranes, etc., there were several power stations, the rolling mills for strip material and for 60 ft. rails, and all the steel furnaces with their complicated systems of flues. If variety is the spice of life, then there was plenty here.
  1944 November and December, A Former Pupil, “Some Memories of Crewe Works—II”, in Railway Magazine, page 341
3. (archaic, printing) A wooden block used for forcing down the type in a form, and making the surface even.
  Quotations
  the compositor "planes down" the "forme," to make a the surface of the type stand flat and even, by blows of the mallet upon a piece of smooth wood laid upon the pages, called, from its use, "a planer;" and it is then ready for the pressman
  1825, Thomas Curson Hansard, Typographia, an Historical Sketch of the Origin and Progress of the Art of Printing