I found several semi-periods in my research.

The synodic periods of the planets vary in length.

During critical periods, children are more sensitive to learning certain skills.

The Sothic periods occur every 1461 years.

Women experience ovulatory periods throughout their reproductive years.

During probationary periods, employees are evaluated to determine their suitability for the job.

The time periods for the project are clearly defined.

There are many periods of time in history that are worth studying.

The company's financial statements for the closed periods are now available.

The operational service periods of the soldiers were extended due to the ongoing conflict.