The point in the temperature range at which a given oil (especially diesel oil ) in vapor form will ignite and flash into flame. The higher the flash point, the better the lubricating quality of the oil. The temperature at which the vapor continues to burn is called the "fire point."
FLASH POINT
Meaning of FLASH POINT in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012