Three times a week. An expression indicating frequency of occurrence.
彼はジムに週三回通っている。
He goes to the gym three times a week.
授業は週三回、火・木・土に行われます。
Classes are held three times a week, on Tue., Thu., and Sat.
医師は薬を週三回服用するように指示した。
The doctor instructed me to take the medicine three times a week.