Appearing or taking place every two weeks or twice a week: [as adjective]: a biweekly bulletin. More example sentences. 1  Black Box is a class that gives students the chance to write, direct, and act in the five different biweekly shows in Studio Two, which is located behind the main stage of the SFU theatre.ppearing or taking place every two weeks or twice a week: [as adjective]: a biweekly bulletin. More example sentences. 1  Black Box is a class that gives students the chance to write, direct, and act in the five different biweekly shows in Studio Two, which is located behind the main stage of the SFU theatre.