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]
(..) There are some rules and regulations. Go out only at night. If you must go out during the daylight, only the East Village. Hey, hey, hey, hey! Name and planet of origin? Sylona Gorth. Planet Jorn. Kaluth system. - Any fruits or vegetables? - Yeah, two heads of cabbage. Reason for visit? (..)2002 Men in Black II