I had a quick Google and found this in an official report on the 1851 census
http://tankona.free.fr/censusuk1851.pdf"The full extent o f the migration can only be
shown by reference to the ages of the people;
as it is certain that great numbers of those
who during childhood and youth remain in
their native place, leave it in after years.
Accordingly, it will be observed that in all
the tables, where the birth-places o f those
under 20, and of those at and above that age,
are now for the first time distinguished, the
proportion o f the adults who have immigrated
m every district is much greater than the pro-
portion of children and young persons."
So I would take it to mean the place where someone was born. Though no doubt, as with everything, you cannot be sure about what was meant or how a word was used.