The Collaborative International Dictionary of English v.0.48:

Isochronize \I*soch"ro*nize\, v. t. [imp. & p. p. -nized; p.
   pr. & vb. n. -nizing.] [See Isochronous.]
   To make, or tend to make (the motion of a moving body),
   uniform in rate of rotation, or in frequency of vibration.
   [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Syntonize \Syn"to*nize\, v. t. [imp. & p. p. -nized; p. pr. &
   vb. n. -nizing.] [See Syntony.] (Physics)
   To adjust or devise so as to emit or respond to electric
   oscillations of a certain wave length; to tune; specif., to
   put (two or more instruments or systems of wireless
   telegraphy) in syntony with each other. --
   Syn`to*ni*za"tion, n.
   [Webster 1913 Suppl.]