A »Mauer« ...
- is a three-dimensional man-made building or a part of a man-made building
- is made from a hard and durable material like concrete, stone or bricks
- has no (small) holes. (Big holes are for doors and windows.)
- has always the purpose to separate areas from each other
- has sometimes the purpose to carry those parts of a building, that are located above the Mauer
- has two big sides which are called »Wände« (plural of »Wand«) (only the two big surfaces are called »Wände«. The surfaces on the both ends, as well as the surface on top or at the bottom are not called »Wände«)
A »Wand« ...
- is a two-dimensional surface (There are exceptions, see »Spanische Wand« below)
- has an upright orientation, i.e. it is not parallel to the floor; It stands orthogonal to the floor. (Also for this exist exceptions, see »Darmwand« below)
- can be the inner or outer surface of a »Mauer« (Innenwand und Außenwand einer Mauer, inside wall and outside wall of a wall)
- can be the steep and almost vertical surface of a mountain (Eiger-Nordwand; Eiger North Face)
- can be the surface on which you project pictures or movies (Bildwand, Leinwand; projection screen)
- can be the front of an upcoming storm (Gewitterwand, Thunderstorm wall)
- can also be a furniture that is made to hide behind while chancing clothes (Spanische Wand; Folding screen) (in this case the »Wand« is a three-dimensional, but flat, object)
- can be the surface that bounds a hollow area (Darmwand; intestinal wall; this is an example where a Wand don't need to be upright)
(False-Friend-Alarm! In english this is not "
wall". It is: rampart, bank or ridge)
A »Wall« ...
- is very similar to a Mauer, so most properties of »Mauer« listet above match here too.
- is very often made of compressed earth
- is often thicker that a Mauer
- is not part of a building (a »Wall« is always a building for itself)
- never has holes (a »Wall« has no doors and no windows)
A »Zaun« ...
- is like a thin and less stable »Mauer«.
- has lots of little holes where you can see through.
- is made of wooden slats, netting wire or sometimes of living plants (like Thuja).
exception Wand <-> Mauer
There is a special case when can you use »Wand« instead of »Mauer«: Often you have the inner walls of a building not built from concrete or stone, but gypsum boards ("drywall"). Such inner walls in buildings are often not called »Mauer« but »Wand«:
Die Wände im Hotel waren sehr dünn, man konnte alle Geräusche aus dem Nebenzimmer hören.
This also is transferred to the outer walls of a building when you tall about their thickness. You use the word »Wandstärke« to talk about the thickness of a wall, even if it is built from concrete, bricks or stone:
Das Mauerwerk alter Kirchen kann im Fundament Wandstärken von mehren Metern haben.
picture on the wall
You can hang a picture on a »Wand«. You also can hang it on a »Mauer«, but in this case you in fact will hang it on one of it's »Wände«. So you better use »Wand« in this case.
But you can also paint pictures directly on a Wand/Mauer. The »Berliner Mauer« (Berlin Wall) was covered all over with graffiti, which are pictures painted (or more often sprayed) on walls. You can have graffiti on a »Wand«, but more often you say it's on a »Mauer«.