Fuze is the universally accepted spelling for any explosive initiator in artillery, bomb or rocket ordnance and has been since the 1800s. It is the accepted NATO definition.
Fuse is an electrical safty device or pyrotechnic timing device, it is not a synonym. It is never used by manufacturers or military.
There is much confusion caused by Google autocomplete and autocorrect which does not recognise the difference.
OK, but you still defuse a bomb. Shouldn’t you defuze it?
A situation evolves slowly, so it is appropriate to defuse it like a slow burning pyrotechnic fuse.
A bomb has an instantaneous fuze (even if a delay is fitted) so it should be defuzed.
OK, that’s clear now, thanks.
Mercury fulminate vs. gunpowder-filled cord, right?
A good analogy.
Minor point: Mercury fulminate is very rarely used as a primary explosive. It has been superceded by Lead Azide, Lead styphanate and tartrazine.
Gunpowder impregnated cord is often referred to a Bicford Safety Fuse or its modern plastic coated type, Visco Fuse.