der
Durchmesser
📏 What does "der Durchmesser" mean?
Der Durchmesser is a German noun that translates to diameter in English. It refers to the longest possible straight line segment (chord) passing through the center of a circle or sphere, with its endpoints lying on the circumference or surface.
It's a fundamental measurement in geometry and engineering. The word is always masculine, so the article is always der.
- Main meaning: Measurement of the width of a round object (circle, sphere, pipe, etc.) through its center.
Article rules for der, die, and das
-er → mostly masculine.
1. Caution: many exceptions. 2. almost all -euer nouns are neutral. 3. There are many -er words, we don't list them all.
🔬 Grammar in Detail: Der Durchmesser
The noun "Durchmesser" is masculine. Here are the declension tables:
| Case | Article | Noun |
|---|---|---|
| Nominative | der | Durchmesser |
| Genitive | des | Durchmessers |
| Dative | dem | Durchmesser |
| Accusative | den | Durchmesser |
| Case | Article | Noun |
|---|---|---|
| Nominative | die | Durchmesser |
| Genitive | der | Durchmesser |
| Dative | den | Durchmessern |
| Accusative | die | Durchmesser |
Example Sentences
- Der Durchmesser dieses Kreises beträgt 10 Zentimeter.
(The diameter of this circle is 10 centimeters.) - Wir müssen den Durchmesser des Rohres genau messen.
(We need to measure the diameter of the pipe accurately.) - Der Baum hat einen beeindruckenden Durchmesser erreicht.
(The tree has reached an impressive diameter.) - Mit dem Durchmesser können wir die Fläche berechnen.
(With the diameter, we can calculate the area.)
🔧 When to use "der Durchmesser"?
"Der Durchmesser" is primarily used in mathematical, technical, and scientific contexts, but also in everyday life when referring to round objects.
- Mathematics/Geometry: Calculating areas of circles, volumes of spheres or cylinders. (Der Durchmesser ist doppelt so lang wie der Radius. - The diameter is twice as long as the radius.)
- Technology/Engineering: Specifying dimensions for pipes, screws, drill holes, cables, etc. (Bitte ein Rohr mit einem Innendurchmesser von 50 mm. - Please provide a pipe with an inner diameter of 50 mm.)
- Natural Sciences: Describing cells, planets, or other round structures. (Der Durchmesser der Erde am Äquator ist etwa 12.756 km. - The Earth's diameter at the equator is about 12,756 km.)
- Everyday Life: Describing the size of round items like plates, pizzas, or tree trunks. (Welchen Durchmesser soll die Geburtstagstorte haben? - What diameter should the birthday cake have?)
It's a precise term and rarely replaced by colloquial alternatives when exact measurements are needed.
🧠 Mnemonics for "der Durchmesser"
For the article 'der': Think of der measurer - a masculine concept, like a tool or a person who measures. The word 'Durchmesser' sounds like 'measure'.
For the meaning: Break it down: "Durch-" means 'through' and "-messer" relates to 'messen' (to measure). So, it literally means the 'through-measure' – the measurement straight through the center.
🔄 Synonyms and Related Terms
Synonyms (often context-dependent):
- Kaliber (das): (Caliber; especially for firearms or pipes)
- Querschnitt (der): (Cross-section; can refer to non-round shapes too, but often describes the 'width')
- Weite (die): (Width/gauge; more for openings, e.g., pipes - 'lichte Weite' = internal width/diameter)
⚠️ Be careful: While Querschnitt is sometimes used similarly, Durchmesser specifically refers to the longest chord through the center of a round object.
😄 A Little Joke
DE: Warum ist der Kreis so optimistisch?
Weil er unendlich viele positive Seiten hat und immer einen klaren Durchmesser! 😉
EN: Why is the circle so optimistic?
Because it has infinitely many positive sides and always a clear diameter! 😉
✍️ Poem about the Diameter
DE:
Ein Kreis, so rund und vollkommen klar,
braucht ein Maß, das ist wunderbar.
Man zieht 'ne Linie, kerzengrad,
von Rand zu Rand, durchs Zentrum spat.
Der Durchmesser, so heißt die Spur,
zweimal der Radius, reinste Natur.
EN:
A circle, so round and perfectly clear,
needs a measure, wonderfully dear.
A line is drawn, perfectly straight,
from edge to edge, through the center late.
The diameter, that's the trace,
twice the radius, nature's pure grace.
❓ Riddle Time
DE:
Ich messe quer durch runde Sachen,
vom Rand zum Rand, ich lass es krachen.
Durch den Mittelpunkt muss ich gehen,
um die volle Breite zu sehen.
In Mathe und Technik bin ich wichtig,
mein Name ist...?
(Lösung: der Durchmesser)
EN:
I measure across round things so wide,
from edge to edge, with nowhere to hide.
Through the center, my path must wend,
to show the full breadth, my friend.
In math and tech, I'm key, you see,
My name is...?
(Answer: der Durchmesser / the diameter)
🧩 Other Information
Word Composition:
The word "Durchmesser" is composed of:
- durch: preposition/adverb meaning 'through'.
- Messer: Here not the knife ('das Messer', neuter), but derived from the verb 'messen' (to measure). It literally means 'that which measures through' or the 'through-measurer'.
Interestingly, 'das Messer' (knife) is neuter, but 'der Messer' (as in 'measurer', e.g., 'Landvermesser' - surveyor) is masculine, aligning with the article 'der' for Durchmesser.
Summary: is it der, die or das Durchmesser?
The word "Durchmesser" for the geometric measurement (diameter) is always masculine. The correct form is: der Durchmesser.