This is the 201st most frequent Hebrew word.
באותו
"In the same" or "at the same."
The word "באותו" is used here to specify a particular day from the context discussed.
באותו יום הלכנו לים.
On that day, we went to the beach.
The word "באותו" refers to the specific building mentioned or implied before.
הם גרו באותו בניין במשך שנים.
They lived in the same building for years.
The word "באותו" indicates a repeated or known location referenced earlier.