m-naught

from The Collaborative International Dictionary of English v.0.48

M'-Naught \M'-Naught"\ (mak*n[add]t"), v. t. (Steam Engines)
   To increase the power of (a single-cylinder beam engine) by
   adding a small high-pressure cylinder with a piston acting on
   the beam between the center and the flywheel end, using
   high-pressure steam and working as a compound engine, -- a
   plan introduced by M'Naught, a Scottish engineer, in 1845.
   [Webster 1913 Suppl.] Mnemonic