Thereby

W opisie nieruchomości użyto thereby, którego znaczenia nie rozumiem:

Age (year built): circa 1970
Gross internal floor area (m²): 100 or thereby
Conservatories / porches: not applicable

w tym słowniku znalazłem znaczenie:
2. archaic by or near that place; thereabouts
https://www.thefreedictionary.com/thereby

Czy thereby oznacza tutaj circa, estimated?

widocznie tak

It seems so. It's combination of words 'there' and 'by'. And it fits as '100 or something around this'.
You can translate it as circa or approximated.

'circa' tez moze byc 'round about'. ..pochodzace mniej wiecej z tego okresu.
This picture was painted circa 1800.
The house was built circa 1600.

Dziękuję