Spontaneous combustion occurs when an object or substance ignites without the presence of an external heat source. There are several synonyms for this peculiar phenomenon. Some of the most commonly used phrases include "self-ignition," "self-heat," and "autoignition." Other similar terms include "self-combustion," "self-heating," and "heat of oxidation." These terms are often used interchangeably to describe the same phenomenon and appear in scientific literature or news reports. While spontaneous combustion is a rare occurrence, it has been known to happen to materials such as hay, coal, and oil-soaked rags. Understanding the various synonyms for spontaneous combustion can help researchers and scientists better identify, study, and prevent these dangerous events from happening.