chrono-, chron-

1. A line (imaginary or on a map) connecting points at which a particular event occurs or occurred at the same time: The isochron ratio chart showed a group of rocks and mineral samples that had been formed at the same time.
2. A line (imaginary or on a map) connecting points on the sea-floor formed at the same time: In class the students were told to prepare a isochron of a cross section of the ocean crust with linking points of the same age.

1. Referring to something taking place in uniform time or at regular intervals: All the periods or classes in school were isochronal because each one of them lasted exactly 45 minutes and followed by a break of 10 minutes.
2. Pertaining to things equal in time; contemporary; occurring during the same time: Mary had two clocks with pendulums which were isochronous and swung back and forth at the same time and kept perfect time!

A line on a chart connecting all points having the same time of occurrence of particular phenomena or of a particular value of a quantity: An isochrone on the map linked the towns and cities from which it would take exactly the same time for Mary and Dick to travel to their destination.

1. The state of having the same chronaxie: Isochronia pertains to keeping the lowest limit of time that an electric current two times the threshold power must flow in order to stimulate a tissue.
2. Agreement, with respect to time, rate, or frequency, between processes: Isochronia is the correspondence of events with respect to time, rate, or frequency.

Referring to something occurring at the same time or at a regular time: Sue's heartbeats were always isochronic, because they always beat in a steady and uniform way.

An isochronous pendulum or watch balance has the characteristics of a uniform rate of operation or periodicity.

1. Something that takes place in or occupies equal times; equal in metrical length; equal in duration, or in intervals of occurrence: Isochronism can be exemplified by the vibrations of a pendulum, or characterized by, or relating to vibrations or motions of equal duration, or the vibrating uniformly as in a metronome.
2. Something that takes place (vibrating, etc.) at the same time, or at the same intervals of time, as something else; equal in duration (vibration-period, etc.) to or with something else: The isochronism of time can be illustrated by all the clocks in Germany that show the same time, especially useful for news broadcasts being presented at exactly eight o'clock in the evening all over Germany.

A clock designed to keep very accurate time: In the science fiction movie, the main character looked at the isochronon to check out the exact time when her servant was to come into the room.

1. An error in chronology: A condition of metachronism occurred when the secretary placed one of the dates of the upcoming events later than it was supposed to happen.
2. In biology, the co-ordination of the movement of parts: Metachronism takes places especially when cilia moves in a progressive wave.

1. In medicine, not synchronous; multiple separate occurrences: The doctor told Mrs. Smith that the case of cancer she had had could be metachronous in that it could develop again at a different time.
2. In geology, referring to a formation that occurred at different times: Professor Jones talked about the metachronous shorelines being of a late-glacial period of geological history.

1. Relating to something occurring at a single period of time; contemporaneous: The accumulation of organic remains can be monochronic in that they were deposited at the same period.
2. Concerning a system where activities are done one at a time: When doing housework, Jane was certainly monochronic in that she first completed one task before starting the next one.

1. In ancient prosody, descriptive of something consisting in or equal to one time or mora; monosemic: In a literal meaning, a monochronous syllable in a word is comprised of a single semeion.
2. Concerning the feature of an expression having only one meaning; a lack of ambiguity: Ivy's mother used only one word which had only one important message, and that was "No!"

An instrument for timing a muscular impulse: The doctor explained that he would use a myochronoscope on Jim's foot to measure the interval between the application of the stimulus and the foot's muscular movement in response.

A technique that attempts to estimate the age of astronomical objects: Dr. Star used the method of nucleocosmochronology to measure the relative abundances of isotopes (any of two or more atoms of an element having the same number of protons, but a different number of neutrons in its nucleus) in his research.

An instrument for measuring very short time intervals: In preparing for the upcoming sports events in the district, an oligochronometer had to be organized in order to determine the exact and precise timing in the races of the athletes.

In geology, a geochronology that is based on a standard biostratigraphical succession of significant faunas or floras, or on irreversible evolutionary processes: Dr. Smart did research in the area of orthochronology to find out more about animals and plants in the irreversible process of evolution.