What is the difference between flashpoint and auto ignition temperature?

Flashpoint is the lowest temperature at which a liquid can vaporize to form an ignitable mixture in air, indicating the point at which it can catch fire if an ignition source is present. In contrast, autoignition temperature is the minimum temperature at which a substance will spontaneously ignite without an external ignition source. Essentially, flashpoint requires an external spark or flame to ignite, while autoignition temperature indicates the temperature at which the substance ignites on its own.