The Collaborative International Dictionary of English v.0.48:
Isochronal \I*soch"ro*nal\, a. [See Isochronous.] Uniform in time; of equal time; performed in equal times; recurring at regular intervals; as, isochronal vibrations or oscillations. [1913 Webster]WordNet (r) 3.0 (2006):
isochronal adj 1: equal in duration or interval; "the oscillations were isochronal" [syn: isochronal, isochronous]