Generally, a<unk>  means a<unk>  which may catch fire easily.
In the USA, there is a precise definition of<unk>  as one with a flashpoint below 100 degrees Fahrenheit. Less-flammable<unk> s (with a flashpoint between 100 degrees and 200 degrees Fahrenheit) are defined as combustible<unk> .  This definition is used by the National Fire Protection Association, The US Department of Transportation, the US Environmental Protection Agency, the US Occupational Safety and Health Administration and others.
These categories are further subdivided, depending on the<unk> 's flash point and boiling point.
Class IA<unk> s have a flash point below 73 °F and a boiling point below 100 °F
Class IB<unk> s have a flash point below 73 °F and a boiling point greater than or equal to 100 °F
Class IC<unk> s have a flash point greater than or equal to 73 °F and below 100 °F
Class II combustible<unk> s have a flash point greater than or equal to 100 °F and below 140 °F
Class IIIA combustible<unk> s have a flash point greater than or equal to 140 °F and below 200 °F
Class IIIB combustible<unk> s have a flash point greater than or equal to 200 °F
Flammable liquid
Liquid
Inhalant
Stye
Biological pigment
Floater
Aqueous solution
Flammability