This is the 13746th most frequent Polish word.
podręcznik
Textbook.
Here, "podręcznik" is used to mean a study textbook, relevant to learning a subject.
Kupuję nowy podręcznik do języka polskiego.
I am buying a new textbook for Polish language.
In this sentence, "podręcznik" refers to a book that provides instructional material combined with exercises.
Ten podręcznik zawiera wiele ciekawych ćwiczeń.
This textbook contains many interesting exercises.
Here, "podręcznik" is described as an authored publication used for instructional purposes.