browse words by letter
a b c d e f g h i j k l m n o p q r s t u v w x y z
epoch

more about epoch

epoch


  4  definitions  found 
 
  From  Webster's  Revised  Unabridged  Dictionary  (1913)  [web1913]: 
 
  Epoch  \Ep"och\  (?;  277),  n.  [LL.  epocha,  Gr  ?  check,  stop,  an 
  epoch  of  a  star,  an  historical  epoch,  fr  ?  to  hold  on 
  check;  'epi`  upon  +  ?  to  have  hold  akin  to  Skr.  sah  to 
  overpower,  Goth.  sigis  victory,  AS  sigor,  sige,  G.  sieg:  cf 
  F.  ['e]poque.  See  {Scheme}.] 
  1.  A  fixed  point  of  time,  established  in  history  by  the 
  occurrence  of  some  grand  or  remarkable  event;  a  point  of 
  time  marked  by  an  event  of  great  subsequent  influence;  as 
  the  epoch  of  the  creation;  the  birth  of  Christ  was  the 
  epoch  which  gave  rise  to  the  Christian  era. 
 
  In  divers  ages,  .  .  .  divers  epochs  of  time  were 
  used  --Usher. 
 
  Great  epochs  and  crises  in  the  kingdom  of  God. 
  --Trench. 
 
  The  acquittal  of  the  bishops  was  not  the  only  event 
  which  makes  the  30th  of  June,  1688,  a  great  epoch  in 
  history.  --Macaulay. 
 
  Note:  Epochs  mark  the  beginning  of  new  historical  periods, 
  and  dates  are  often  numbered  from  them 
 
  2.  A  period  of  time,  longer  or  shorter,  remarkable  for  events 
  of  great  subsequent  influence;  a  memorable  period;  as  the 
  epoch  of  maritime  discovery,  or  of  the  Reformation.  ``So 
  vast  an  epoch  of  time.''  --F.  Harrison. 
 
  The  influence  of  Chaucer  continued  to  live  even 
  during  the  dreary  interval  which  separates  from  one 
  another  two  important  epochs  of  our  literary 
  history.  --A.  W.  Ward. 
 
  3.  (Geol.)  A  division  of  time  characterized  by  the  prevalence 
  of  similar  conditions  of  the  earth;  commonly  a  minor 
  division  or  part  of  a  period. 
 
  The  long  geological  epoch  which  stored  up  the  vast 
  coal  measures.  --J.  C. 
  Shairp 
 
  4.  (Astron.) 
  a  The  date  at  which  a  planet  or  comet  has  a  longitude  or 
  position. 
  b  An  arbitrary  fixed  date,  for  which  the  elements  used 
  in  computing  the  place  of  a  planet,  or  other  heavenly 
  body,  at  any  other  date,  are  given  as  the  epoch  of 
  Mars;  lunar  elements  for  the  epoch  March  1st,  1860. 
 
  Syn:  Era;  time;  date;  period;  age. 
 
  Usage:  {Epoch},  {Era}.  We  speak  of  the  era  of  the 
  Reformation,  when  we  think  of  it  as  a  period,  during 
  which  a  new  order  of  things  prevailed;  so  also  the 
  era  of  good  feeling,  etc  Had  we  been  thinking  of  the 
  time  as  marked  by  certain  great  events,  or  as  a  period 
  in  which  great  results  were  effected,  we  should  have 
  called  the  times  when  these  events  happened  epochs, 
  and  the  whole  period  an  epoch. 
 
  The  capture  of  Constantinople  is  an  epoch  in  the 
  history  of  Mahometanism;  but  the  flight  of 
  Mahomet  is  its  era.  --C.  J.  Smith. 
 
  From  WordNet  r  1.6  [wn]: 
 
  epoch 
  n  1:  a  period  marked  by  distinctive  character  or  reckoned  from  a 
  fixed  point  or  event  [syn:  {era}] 
  2:  (astronomy)  the  precise  date  that  is  the  point  of  reference 
  for  which  information  (as  coordinates  of  a  celestial  body) 
  is  referred  [syn:  {date  of  reference}] 
  3:  a  unit  of  geological  time 
 
  From  Jargon  File  (4.2.3,  23  NOV  2000)  [jargon]: 
 
  epoch  n.  [Unix:  prob.  from  astronomical  timekeeping]  The  time 
  and  date  corresponding  to  0  in  an  operating  system's  clock  and  timestamp 
  values.  Under  most  Unix  versions  the  epoch  is  00:00:00  GMT,  January  1, 
  1970;  under  VMS,  it's  00:00:00  of  November  17,  1858  (base  date  of  the 
  U.S.  Naval  Observatory's  ephemerides);  on  a  Macintosh,  it's  the  midnight 
  beginning  January  1  1904.  System  time  is  measured  in  seconds  or  {tick}s 
  past  the  epoch.  Weird  problems  may  ensue  when  the  clock  wraps  around 
  (see  {wrap  around}),  which  is  not  necessarily  a  rare  event;  on  systems 
  counting  10  ticks  per  second  a  signed  32-bit  count  of  ticks  is  good 
  only  for  6.8  years.  The  1-tick-per-second  clock  of  Unix  is  good  only 
  until  January  18,  2038,  assuming  at  least  some  software  continues 
  to  consider  it  signed  and  that  word  lengths  don't  increase  by  then. 
  See  also  {wall  time}.  Microsoft  Windows,  on  the  other  hand,  has  an 
  epoch  problem  every  49.7  days  -  but  this  is  seldom  noticed  as  Windows 
  is  almost  incapable  of  staying  up  continuously  for  that  long. 
 
 
 
  From  The  Free  On-line  Dictionary  of  Computing  (13  Mar  01)  [foldoc]: 
 
  epoch 
 
  1.  [Unix:  probably  from  astronomical  timekeeping]  The  time  and 
  date  corresponding  to  0  in  an  operating  system's  clock  and 
  timestamp  values.  Under  most  Unix  versions  the  epoch  is 
  00:00:00  GMT,  January  1,  1970;  under  VMS,  it's  00:00:00  of 
  November  17,  1858  (base  date  of  the  US  Naval  Observatory's 
  ephemerides);  on  a  Macintosh,  it's  the  midnight  beginning 
  January  1  1904.  System  time  is  measured  in  seconds  or  {tick}s 
  past  the  epoch.  Weird  problems  may  ensue  when  the  clock  wraps 
  around  (see  {wrap  around}),  which  is  not  necessarily  a  rare 
  event;  on  systems  counting  10  ticks  per  second  a  signed 
  32-bit  count  of  ticks  is  good  only  for  6.8  years.  The 
  1-tick-per-second  clock  of  Unix  is  good  only  until  January  18, 
  2038,  assuming  at  least  some  software  continues  to  consider  it 
  signed  and  that  word  lengths  don't  increase  by  then.  See  also 
  {wall  time}. 
 
  2.  (Epoch)  A  version  of  {GNU  Emacs}  for  the  {X  Window  System} 
  from  {NCSA}. 
 
  [{Jargon  File}] 
 
 




more about epoch