The 'origin' of this custom/tradition is not known. = The 'origins' of this custom/tradition are not known. [=no one knows how this custom/tradition started]
He comes from 'humble origins'. [=he comes from a family that did not have high social status or much money]
The English word “rendezvous” is French 'in origin'. [=the English word comes from French]
(..) ? That's after the plague. Why would she go there? Because there was another plague... one that ravaged time itself... a plague whose origins can be traced back to one single moment. No cult. No investigation needed. The true catalyst for the destruction of mankind is standing before your eyes. (..)2016 TvShow: 12 Monkeys Title: Lullaby Season: 2 Episode 8