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Occurring without periodicity; irregular.

a′pe·ri·od′i·cal·ly adv.
a·pe′ri·o·dic′i·ty (-ə-dĭs′ĭ-tē) n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. not periodic; not occurring at regular intervals
2. (General Physics) physics
a. (of a system or instrument) being damped sufficiently to reach equilibrium without oscillation
b. (of an oscillation or vibration) not having a regular period
c. (of an electrical circuit) not having a measurable resonant frequency
ˌaperiˈodically adv
aperiodicity n
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌeɪ pɪər iˈɒd ɪk)

1. not periodic; irregular.
2. Physics. of or pertaining to vibrations or oscillations with no apparent period.
a`pe•ri•od′i•cal•ly, adv.
a•pe`ri•o•dic′i•ty (-əˈdɪs ɪ ti) n.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.aperiodic - not recurring at regular intervals
periodic, periodical - happening or recurring at regular intervals; "the periodic appearance of the seventeen-year locust"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
36.38) for three types of materials of wires cores and cables (copper, aluminum and steel) used in determining the final temperature [[theta].sub.k] of Joule heating by SC current of the current transmission parts of CCP do not fully describe the features of the process of approximate calculation of the numerical values of the specified integral [B.sub.k] and allowable cross sections [S.sub.lmin] (for example, selecting the amplitude-time parameters (ATPs) for these purposes of periodic and aperiodic components of the SC current, duration [t.sub.kC] of the SC process, etc.).
However, specialty fibres such as aperiodic fibre Bragg gratings have been shown to provide a platform for highly complex OH suppression filters [2].
The El Nino/La Nina cycle is rather aperiodic, with an average period of about four to five years.
Its usage helps to improve the accuracy of the fault location determination, thanks to such advantages as high accuracy of the measurement (current and voltage error [less than or equal to] 0.1%), wide frequency range of the measurement including the direct current measurement, and absence of the saturation caused by short-circuit current and aperiodic component.
The phase diagram in Figure 4(d) is not closed for Q= 10 at the outset, emerging as a tangle of interlaced curves, which means that the system is aperiodic and unstable.
In addition, the BOC sequence, which is commonly used in secret communications, has a longer period or is aperiodic in a short time, which increases the difficulty of detecting and estimating the BOC signal.
Kalyaniwalla, "Competition model for aperiodic stochastic resonance in a Fitzhugh-Nagumo model of cardiac sensory neurons," Physical Review E, Statistical, Nonlinear, and Soft Matter Physics, vol.
where t is the measurement time, [DELTA][[delta].sub.u](t) is the periodic error component, and [DELTA][[delta].sub.e](t) is the aperiodic error component.
Tsur ("Size-Sound Symbolism Revisited") argues that periodic consonants (e.g., [m], [n]) are perceived as soft, mellow, and appeasing, whereas aperiodic continuants (e.g., [s], [z]) as harsh, strident, turbulent, and the like.
It works well with patients whose vocal folds vibrate in a periodic or pseudoperiodic fashion; however, it is not optimal for assessment of aperiodic vibration because the frequency detection system of the stroboscope cannot track rapid, irregular changes effectively.