And also in Tongan. But it is used as a description, when there are two or more people with the same name alive at the same time in the same family eg Sione Lahi and Sione si'i
John the older/ bigger and John the younger/ smaller. They do not have to be father and son ie senior and junior, just one older and one younger and related somehow.
So the likelihood is that this lady was the older of two people with the same name in the same family at that time.