Feuer vs. Brand, and Wall vs. Mauer

The story so far: Someone suggests translating ``firewall'' as ``Feuerwand.'' The actual term would be ``Brandmauer''.

Okay, then what's the difference between Feuer and Brand, *and* what's the difference between Wand and Mauer?

Feuer is the more primitive, more general term. Brand is derived from the verb brennen, "to burn", and is mostly used for a destructive, accidental fire. I.e. a bushfire is a Waldbrand (forest burn), you can get insurance against Hausbrand (house burn); but the campfire you roast marshmallows on would be a Lagerfeuer; the fire in a stove is a Herdfeuer, one in a fireplace a Kaminfeuer. (Kamin is a chimney.)

A Wand refers to the geometric configuration that delimits space, Mauer to the building of walls from stones (mauern is the verb; a mason is a Maurer. It's probably related to mural.) Not every Wand is made out of stone: it could be made from paper, or just a cardboard dividers used to separate cubicles; cells in an organic body are separated by Zellwände (cell walls); a bulletin board is a Pinnwand.

A Mauer is very likely made from stone; mauern is also used figuratively to mean "blocking, not talking";

Ich hab' versucht, mehr aus ihm 'rauszukriegen, aber er hat gemauert.
I've tried to extract more [information] from him, but he stonewalled me.
In soccer, the human wall built from players clutching their genitals (I have no idea where female soccer players put their hands in that situation) is also called Mauer, not Wand. (Possibly for the stronger connotation of impenetrability?)

German speakers might be familiar with a children's tune that starts

Auf der Mauer, auf der Lauer, liegt 'ne kleine Wanze.
On the wall, lurking, lies a little bedbug. (Which doesn't make a whole lot of sense since, as far as I heard, the little bedbug is more likely to lurk behind the tapestry, stuck to the wall, than on top of it.)
There's also the word Wall in German, which is a thick wall used to ward off intruders.

The strongest implication of the use of Brandmauer rather than Feuerwand is that the word is one that originated in architect's jargon; I find that, at least in German jargon, construction-based and more specific references are more likely than general ones.

The word Feuerwand, although uncommon, could be used in an article about the work of firemen (Feuerwehrmänner - not Brandwehrmänner, I have no idea why) to describe a wall consisting of fire.

Comments, corrections, flames to jutta@cs.tu-berlin.de.