But it is strictly correct. Deflagration is the definition of low (i.e. subsonic) explosive.
Combustion is a broader term — combustion just refers to burning. And the reason it is called an internal combustion engine is to contrast it from its predecessor combustion engine designs - the external combustion engine.
More precisely, the type of combustion happening in an ICE engine is (low) explosive.
and that is not strictly correct. it's called combustion engine and not explosion engine for a reason.
But it is strictly correct. Deflagration is the definition of low (i.e. subsonic) explosive.
Combustion is a broader term — combustion just refers to burning. And the reason it is called an internal combustion engine is to contrast it from its predecessor combustion engine designs - the external combustion engine.
More precisely, the type of combustion happening in an ICE engine is (low) explosive.
https://en.wikipedia.org/wiki/Explosive#Low