Source : Webster's Revised Unabridged Dictionary (1913)

Scotch \Scotch\, v. t. [imp. & p. p. {Scotched}; p. pr. & vb. n.
   {Scotching}.] [Cf. Prov. E. scote a prop, and Walloon ascot a
   prop, ascoter to prop, F. accoter, also Armor. skoaz the
   shoulder, skoazia to shoulder up, to prop, to support, W.
   ysgwydd a shoulder, ysgwyddo to shoulder. Cf. {Scoat}.]
   [Written also {scoatch}, {scoat}.]
   To shoulder up; to prop or block with a wedge, chock, etc.,
   as a wheel, to prevent its rolling or slipping.

Scotching \Scotch"ing\, n. (Masonry)
   Dressing stone with a pick or pointed instrument.