The concept refers to a tool, either physical or computational, designed to divide the nighttime period into three equal segments. For example, if night begins at 6:00 PM and ends at 6:00 AM, each of these segments would be four hours long. Such a division allows for the precise determination of when each of these periods commences and concludes.
The ability to accurately determine these segments holds significance across various religious observances, particularly in Islam where it is used to calculate the optimal times for prayer and spiritual reflection. Historically, estimations relied on observational astronomy and rudimentary timekeeping. The benefit of using a precise method is to ensure adherence to specific religious guidelines with accuracy, replacing approximations based on personal judgment or outdated methods.