This is the 272nd most frequent Arabic word.
الأخرى
The other.
Here, "الآخر" (other) is used to describe a day distinct from the previously mentioned one, thereby specifying a different time context.
ذهبت إلى المكتبة بالأمس، وفي اليوم الآخر زرت المتحف.
I went to the library yesterday, and on the other day, I visited the museum.
"الأخرى" is used here to reference another specific location relative to a previously mentioned or understood point of reference.
في الجهة الأخرى من الشارع توجد الحديقة العامة.
On the other side of the street is the public park.
In this sentence, "الأخرى" (other) specifies one sister among a group, distinguishing her choice from others.