This is the 8105th most frequent Turkish word.
los
The Turkish word "los" refers to "lax," "loose," or "soft."
In this sentence, 'los' is a determiner used for stressing the inclusion or importance of the objects—in this case, books.
Los kitaplarını almayı unuttu.
He/She forgot to take his/her/their books.
In this context, 'los' refers to the entire group of classes, highlighting the inclusivity of all sessions.
Los derslerin sonunda herkes çok şey öğrendi.
At the end of the classes, everyone learned a lot.
Here, 'los' emphasizes the extended period of time (months), signifying a considerable effort.