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## periodical

```  3  definitions  found

From  Webster's  Revised  Unabridged  Dictionary  (1913)  [web1913]:

Periodic  \Pe`ri*od"ic\,  Periodical  \Pe`ri*od"ic*al\,  a.  [L.
periodicus  Gr  ?:  cf  F.  p['e]riodique.]
1.  Of  or  pertaining  to  a  period  or  periods,  or  to  division  by
periods.

The  periodicaltimes  of  all  the  satellites.  --Sir  J.
Herschel.

2.  Performed  in  a  period,  or  regular  revolution;  proceeding
in  a  series  of  successive  circuits;  as  the  periodical
motion  of  the  planets  round  the  sun.

3.  Happening,  by  revolution,  at  a  stated  time;  returning
regularly,  after  a  certain  period  of  time;  acting,
happening,  or  appearing,  at  fixed  intervals;  recurring;
as  periodical  epidemics.

The  periodic  return  of  a  plant's  flowering.
--Henslow.

To  influence  opinion  through  the  periodical  press.
--Courthope.

4.  (Rhet.)  Of  or  pertaining  to  a  period;  constituting  a
complete  sentence.

{Periodic  comet}  (Astron.),  a  comet  that  moves  about  the  sun
in  an  elliptic  orbit;  a  comet  that  has  been  seen  at  two  of
its  approaches  to  the  sun.

{Periodic  function}  (Math.),  a  function  whose  values  recur  at
fixed  intervals  as  the  variable  uniformly  increases.  The
trigonomertic  functions,  as  sin  x,  tan  x,  etc.,  are
periodic  functions.  Exponential  functions  are  also
periodic,  having  an  imaginary  period,  and  the  elliptic
functions  have  not  only  a  real  but  an  imaginary  period,
and  are  hence  called  doubly  periodic.

{Periodic  law}  (Chem.),  the  generalization  that  the
properties  of  the  chemical  elements  are  periodic  functions
of  their  atomic  wieghts.  ``In  other  words  if  the  elements
are  grouped  in  the  order  of  their  atomic  weights,  it  will
be  found  that  nearly  the  same  properties  recur
periodically  throughout  the  entire  series.''  The  following
tabular  arrangement  of  the  atomic  weights  shows  the
regular  recurrence  of  groups  (under  I.,  II.,  III.,  IV.,
etc.),  each  consisting  of  members  of  the  same  natural
family.  The  gaps  in  the  table  indicate  the  probable
existence  of  unknown  elements.

From  Webster's  Revised  Unabridged  Dictionary  (1913)  [web1913]:

Periodical  \Pe`ri*od"ic*al\,  n.
A  magazine  or  other  publication  which  appears  at  stated  or
regular  intervals.

From  WordNet  r  1.6  [wn]:

periodical
adj  :  happening  or  recurring  at  regular  intervals  [syn:  {periodic}]
[ant:  {aperiodic}]
n  :  a  publication  that  appears  at  fixed  intervals
```