German has exactly five coordinating conjunctions, and they are worth memorizing as a closed set because they share one decisive property: they join two clauses of equal rank and leave the word order of both clauses completely untouched. The verb stays in second position on either side of them. This makes them the easiest conjunctions in the language — there is no inversion, no verb hopping to the end, nothing to recalculate. The trap is not the grammar; it is recognizing that one of them, denn, means "because" yet behaves nothing like the "because" word most learners reach for first (weil).
The ADUSO set
The five coordinators are easy to remember with the acronym ADUSO: aber, denn, und, sondern, oder. Their meanings:
| Conjunction | Meaning | Joins |
|---|---|---|
| und | and | addition |
| oder | or | alternatives |
| aber | but | contrast |
| denn | because, for | a reason |
| sondern | but rather | a correction after a negation |
If a conjunction is on this list, it never changes the word order. If it is not on this list, assume it is a subordinating conjunction that sends the verb to the end (weil, dass, wenn, obwohl, and so on). That single dividing line organizes the entire system of German clause-linking.
Position zero: why the word order stays put
A coordinating conjunction sits in what German grammar calls "position zero" (Position null). It is the glue between two clauses, not a member of either one. Because it does not count as part of the second clause, the counting for verb-second order starts fresh: the next clause begins with its own subject (or another front-field element), and the finite verb lands in second position, exactly as if the clause stood alone.
This is the core mechanism, and it is worth stating positively: in English you can say "I'm tired, but I keep working" and nothing about the second half changes. German works the same way after a coordinator — the second clause looks like an ordinary main clause.
Ich bin müde, aber ich arbeite weiter.
I'm tired, but I'm carrying on working. (after 'aber': subject 'ich', then verb 'arbeite' in second position)
Wir können ins Kino gehen, oder wir bleiben einfach zu Hause.
We can go to the cinema, or we'll just stay home. ('oder' joins two normal V2 clauses)
und — addition
Und simply adds. The clause after it keeps subject-then-verb order. When the subject of both clauses is the same person, German often drops the repeated subject in the second clause, which is also natural in English.
Ich stehe um sieben auf und ich trinke sofort einen Kaffee.
I get up at seven, and I immediately drink a coffee. (full second clause, subject repeated)
Sie kommt nach Hause und macht erst mal die Heizung an.
She comes home and first thing turns the heating on. (shared subject dropped; verb 'macht' stays second)
oder — alternatives
Oder offers a choice between two clauses or elements. As with und, no inversion, no comma needed when it merely links clauses.
Trinkst du lieber Tee oder soll ich dir einen Kaffee machen?
Would you rather drink tea, or should I make you a coffee? (informal; both clauses keep V2)
aber — contrast
Aber marks a contrast or qualification. The second clause stays V2. Aber is also extremely common as a flavour word inside a clause (a modal particle), but as a conjunction it links two equals.
Die Wohnung ist klein, aber sie ist wirklich gemütlich.
The flat is small, but it's really cosy. (contrast, no correction — see the aber-vs-sondern page)
denn — the coordinating "because"
This is the one that catches everyone. Denn means "because" (or the slightly old-fashioned English "for"), and it is coordinating — the "D" in ADUSO. So unlike weil, it keeps the verb in second position.
Ich bleibe heute zu Hause, denn es regnet in Strömen.
I'm staying home today, because it's pouring with rain. (denn = coordinating: subject 'es', then verb 'regnet' second)
Wir müssen uns beeilen, denn der Zug fährt in zehn Minuten.
We have to hurry, because the train leaves in ten minutes. (V2 word order in the second clause)
Compare those with the weil versions: Ich bleibe zu Hause, weil es regnet sends the verb to the end (weil es ... regnet). Same meaning, opposite word order. Denn is also a touch more formal and written-sounding; in everyday speech most Germans reach for weil. The full three-way comparison of weil, da, and denn lives on its own page.
sondern — the corrective "but"
Sondern also translates as "but," but it is far more restricted than aber. It is only used to correct a negation — the pattern "not X, but rather Y." The first clause must be negative, and the second replaces what was denied.
Das ist nicht mein Mantel, sondern deiner.
That's not my coat, but rather yours. (negation in clause one, correction in clause two)
Wir fahren nicht am Freitag, sondern erst am Samstag.
We're not leaving on Friday, but rather only on Saturday.
English uses "but" for both contrast and correction, so English speakers tend to use aber everywhere — which is wrong half the time. The trigger to watch for is a negation in the first clause: if the second part corrects that negation, you need sondern, not aber. This split deserves close attention and has its own dedicated page.
Comma rules
German punctuation for coordinators is simple once you separate the five into two groups:
- Always put a comma before aber, sondern, and denn.
- Usually no comma before und and oder when they link clauses — though a comma is allowed before und/oder for clarity, especially when the clauses are long or have different subjects.
| Conjunction | Comma before it? |
|---|---|
| aber | Yes |
| sondern | Yes |
| denn | Yes |
| und | No (optional for clarity) |
| oder | No (optional for clarity) |
Note that all five conjunctions are written lowercase — they are ordinary function words, not nouns. (German capitalizes every noun, but never these.)
Common Mistakes
Using verb-final order after denn — treating it like weil. This is the single most common error, because learners learn weil first and assume every "because" works the same way.
❌ Ich bleibe zu Hause, denn es regnet stark ist.
Incorrect — 'denn' is coordinating; the verb stays in second position, and there's no extra verb to move.
✅ Ich bleibe zu Hause, denn es regnet stark.
I'm staying home, because it's raining hard.
Using aber where sondern is required — because English "but" covers both. The first clause here is negative, so the correction needs sondern.
❌ Das ist nicht rot, aber blau.
Incorrect — after a negation that gets corrected, German requires 'sondern', not 'aber'.
✅ Das ist nicht rot, sondern blau.
That's not red, but (rather) blue.
Forgetting the comma before aber, sondern, or denn.
❌ Ich wollte kommen aber ich hatte keine Zeit.
Incorrect — a comma is required before 'aber'.
✅ Ich wollte kommen, aber ich hatte keine Zeit.
I wanted to come, but I didn't have time.
Inverting the subject after a coordinator — wrongly importing the inversion that conjunctional adverbs (deshalb, trotzdem) trigger. After ADUSO conjunctions, the subject comes first as normal.
❌ Es ist spät, und gehen wir nach Hause.
Incorrect — 'und' is in position zero and does not cause inversion; the subject comes first.
✅ Es ist spät, und wir gehen nach Hause.
It's late, and we're going home.
Key Takeaways
- The five coordinating conjunctions are aber, denn, und, sondern, oder (the ADUSO set).
- They sit in position zero and leave word order alone — the verb stays in second position in both clauses.
- denn is the coordinating "because" (V2); it is not interchangeable with subordinating weil (verb-final).
- sondern is "but" only after a negation it corrects; aber covers all other contrasts.
- Put a comma before aber, sondern, and denn; und and oder normally take none.
Now practice German
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Start learning German→Related Topics
- Coordinating vs Subordinating Conjunctions and Word OrderB1 — The conjunction you choose dictates the word order: coordinating conjunctions leave V2 untouched, subordinating ones send the verb to the end — and 'denn' vs 'weil' proves it.
- Causal Conjunctions: weil, da, dennB1 — German has three words for 'because' — weil, da, and denn — and they differ in both syntax (verb-final vs V2) and discourse (new vs known reason). Here's how to choose.
- aber vs sondern (but)A2 — Both mean 'but', but sondern is used only after a negation it corrects ('not X, but rather Y'), while aber covers every other kind of contrast — the negation in the first clause is your trigger.
- Verb-Second (V2): The Core Rule of German Word OrderA1 — The finite verb is always the second element in a German main clause — exactly one constituent precedes it, and the subject jumps behind the verb whenever something else is fronted.
- Subordinating Conjunctions: OverviewB1 — Every subordinating conjunction — dass, weil, wenn, obwohl, damit and the rest — does the same thing: it sends the finite verb to the end of its clause. Learn the list, and the syntax becomes automatic.
- denn in QuestionsB1 — The particle denn turns a bald question into a warm, engaged one — and why it must not be confused with the conjunction denn ('because').