from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Equal in duration.
  • adjective Characterized by or occurring at equal intervals of time.

from The Century Dictionary.

  • Uniform in time; of equal time; performed in equal times. Two pendulums which vibrate in the same time are isochronal; also, the vibrations of a pendulum in the curve of a cycloid have the same property, being all performed in the same time, whether the arc be large or small. Also isochronous.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Uniform in time; of equal time; performed in equal times; recurring at regular intervals.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective having the same duration
  • adjective happening at regular periods; isochronous, periodic
  • adjective computing, of data time dependent

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective equal in duration or interval


from The American Heritage® Dictionary of the English Language, 4th Edition

[From New Latin īsochronus, from Greek īsokhronos : īso-, iso- + khronos, time.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

isochron +‎ -al


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  • The assumption of isochronal behaviour is always a problem is both open and globular clusters.

    Dating a Cluster – A New Trick | Universe Today 2009

  • Escapement friction plays an important role in the position and isochronal adjustments; the greater the friction encountered the slower the vibration of the balance.

    An Analysis of the Lever Escapement H. R. Playtner

  • There was something indescribably grim and bodeful in those isochronal batterings of the solid ground.

    Joan of Arc of the North Woods Holman Day 1900

  • A trombone blatted -- there was the staccato tuck of a snare drum, and the boom of a bass drum came in with isochronal beats.

    When Egypt Went Broke Holman Day 1900

  • He chewed slowly, conscientiously and continuously on tobacco which bulged in his cheek; his jaws, moving as steadily as a pendulum swings, seemed to set the time for the isochronal whistle-blast.

    Blow The Man Down A Romance Of The Coast - 1916 Holman Day 1900

  • It often happens, however, during the first critical epoch, which is isochronal with the technical educational period of a girl, that after a few occasions of catamenial hemorrhage, moderate perhaps but still hemorrhage, which are not heeded, the conservative force of Nature steps in, and saves the blood by arresting the function.

    Sex in Education or, A Fair Chance for Girls Edward Hammond Clarke 1848


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  • also isochronous

    March 14, 2007

  • That was when I saw the Pendulum.

          The sphere, hanging from a long wire set into the ceiling of the choir, swayed back and forth with isochronal majesty.

    --Umberto Eco, 1988, Foucault's Pendulum, p. 3

    September 29, 2008