This is the 694th most frequent Ukrainian word.
тижнів
"Weeks" (plural form).
Here, "тижнів" represents a duration of time measured in weeks, specifically referring to 'two weeks'.
Через два тижні я поїду у відпустку.
In two weeks, I will go on vacation.
In this context, "тижнів" is used to indicate the length of time (duration) that the course spans.
Цей курс триває шість тижнів.
This course lasts six weeks.
Here, "тижнів" is used to indicate the passage of an indefinite number of weeks since an event.