▁ ▁The ▁term ▁sec ular ▁variation ▁is ▁used ▁wherever ▁time ▁series ▁are ▁applicable ▁ ▁in ▁history , ▁econom ics , ▁operations ▁research , ▁bi ological ▁anth rop ology , ▁astronom y ▁( part icular ly ▁cel est ial ▁mechan ics ) ▁such ▁as ▁VS OP ▁( plan ets ) ▁etc . ▁ ▁Et ym ology ▁The ▁word ▁sec ular , ▁from ▁the ▁Latin ▁root ▁sa ec ular is ▁(" of ▁an ▁age , ▁occurr ing ▁once ▁in ▁an ▁age "), ▁has ▁two ▁basic ▁mean ings : ▁I . ▁Of ▁or ▁per tain ing ▁to ▁the ▁world ▁( from ▁which ▁sec ular ity ▁is ▁derived ), ▁and ▁II . ▁Of ▁or ▁belonging ▁to ▁an ▁age ▁or ▁long ▁period . ▁The ▁latter ▁use ▁appeared ▁in ▁the ▁ 1 8 th ▁century ▁in ▁the ▁sense ▁of ▁" l iving ▁or ▁last ing ▁for ▁an ▁age ▁or ▁ages ". ▁In ▁the ▁ 1 9 th ▁century ▁terms ▁like ▁sec ular ▁acceleration ▁and ▁sec ular ▁variation ▁appeared ▁in ▁astronom y , ▁and ▁similar ▁language ▁was ▁used ▁in ▁econom ics ▁by ▁ 1 8 9 5 . ▁ ▁Astronom y ▁In ▁astronom y , ▁sec ular ▁variations ▁are ▁contrast ed ▁with ▁periodic ▁phen omena . ▁In ▁particular , ▁astronom ical ▁e ph emer ides ▁use ▁sec ular ▁to ▁label ▁the ▁longest - last ing ▁or ▁non - osc ill atory ▁perturb ations ▁in ▁the ▁motion ▁of ▁plan ets , ▁as ▁opposed ▁to ▁periodic ▁perturb ations ▁which ▁exhib it ▁repet ition ▁over ▁the ▁course ▁of ▁a ▁time ▁frame ▁of ▁interest