What is defined as a rapid, persistent chemical reaction that releases both heat and light?

The definition of a rapid, persistent chemical reaction that releases both heat and light aligns closely with the characteristics of fire. Fire is a chemical reaction known as combustion, wherein fuel reacts with an oxidizer (usually oxygen in the air) and produces heat, light, and various combustion by-products.

This reaction occurs continuously as long as there are sufficient fuel and oxygen present, and it is marked by flames, which are visible manifestations of the heat and light energy produced. The persistence of this reaction is a key component in distinguishing fire from other phenomena like explosions or flashover, which may not necessarily involve ongoing combustion processes.

In contrast, terms such as flameover and flashover refer to specific fire events or phenomena related to fire behavior, rather than the fundamental definition of what constitutes fire. An explosion is a rapid, often violent release of energy, but it does not consistently produce the sustained heat and light output associated with a traditional fire.