Noun

1. One skilled in the theory or construction of machines.

   To build such a device will require an expert mechanician.

   • a1891, Constance Garnett (translator), Leo Tolstoy (author), Anna Karenin, in The Harvard Classics Shelf of Fiction, P.F. Collier & son (1917), page 214,

     "The mechanician came when I was away; I haven't seen him yet," he said, not looking at her.

   • The Yankees, the first mechanicians in the world, are engineers-- just as the Italians are musicians and the Germans metaphysicians-- by right of birth. -- from From The Earth To The Moon by Jules Verne.
   • The Cotton-Gin is a machine to separate the seeds from cotton, invented by that celebrated mechanician, E. Whitney. -- from the 1828 Webster's Dictionary.
2. One skilled in building, using, or repairing machines, or who makes machines or tools.
   • Shortly after being removed to the hospital Wright recovered consciousness and sent for Taylor, his mechanician. -- "Fatal fall of Wright airship", New York Times September 18th 1908
3. One skilled in mechanics.
4. A machinist.
5. A scientifically trained practitioner.
6. A mechanic.