Difference between a Bunker and a Pillbox?

Does anyone know the actual difference between these two defences?

I always thought that a Bunker was more of a small defensive structure that contained with a squad of infantry or a machine gun, and a pillbox had any type of antitank weapon in it, but is there an actual official definition of it.

This is all I could find.

Feldgrau.net • View topic - What's the difference between a bunker and a pillbox?

 

I just found this as well

 

Bunker - Wikipedia, the free encyclopedia

Says here that bunkers are basically defensive structures often built fully or partially underground to protect its occupants from outside hazards. Pillboxes are a subcategory of bunkers and are basically dug in guard-posts with embrasures. The name derives from the shape. Seems to me that pillboxes were specifically designed to defend against enemy ground units and could be placed in concordance with other defensive structures in order to form interlocking fields of fire. They could also be camouflaged to maintain the element of surprise against enemies.

 

Yep, bunkers were usually designed as accommmodation/offices, while pillboxes were specifically fighting structures.
The trouble starts when folk confuse semi-sunken pillboxes and bunkers.

 

So it is one of those "is it a hill or a mountain," "A boat or a ship"? It has a general rule about it but there are exceptions?

 

you want to see a bunker.....see my 5 signature you tubes....now thats a bunker...Maginot line would be jelous of.

 

Sunken Pillboxes Guarded Jap Coast

fact or fiction..lol..interesting idea?

 

The OED has;

Bunker; Reinforced underground shelter.

Pill-Box; Small isolated chiefly underground concrete fort.

the British designations for the WW2 ones seems to call them almost all pillboxes regardless of amount underground, if they have embrasures;

British hardened field defences of World War II - Wikipedia, the free encyclopedia

 

My thoughly unscientific definition, if you were attacking it, it looked like a bunker, if you were defending from it, it felt like a pill box!

 

Bunker: In ground smaller sized fortification
Pillbox: Above ground smaller sized fortification