Tibetan month (Wyl. hor zla) is the name we use in English for the months of the Tibetan calendrical year, as opposed to the months of our Gregorian calendar. Its name in Tibetan hor zla means Mongol month, as it was borrowed from the Mongolian way of calculating month. But for us, we borrowed from the Tibetan culture, and call it Tibetan month. These are not exactly lunar months as their calculation is based on both the position of the moon and that of the sun.