This is the 405th most frequent Turkish word.
birinci
"Birinci" means "first" in English.
Here, 'birinci' means 'first' as an ordinal number indicating rank.
Bu yarışta birinci oldum.
I became first in this race.
In this context, 'birinci' signifies the order of books, meaning the 'first' one.
Okuduğum birinci kitap çok etkileyiciydi.
The first book I read was very impactful.
Here, 'birinci' describes positional order as in the 'first' shell of an atom.