Compound Words

German is famous for word monsters like Donaudampfschifffahrtsgesellschaft, compounds long enough to make anyone flinch on sight. Yet in the onSET, one single question cracks every one of them. Take die Wohnungstür: why die and not der or das? Because the last part, Tür, decides the article, no matter what comes before it. That one principle solves every gap that lands at the end or at the seam of a compound in the onSET C-test. Compound nouns belong to the broad group of vocabulary-stem gaps, which make up close to half of the C-test overall; the seam rule itself is just a small, well-defined slice of that, one you can master quickly.

The good news: a compound is always built the same way. The last part, the head noun (Grundwort), carries the grammatical information. It decides the article and the plural. The parts before it, the modifiers (Bestimmungswörter), only say what kind of thing it is. And between the parts there is sometimes a small connector, the seam (Fuge). Let us look at both calmly.

Quick rule: The last word decides gender and core meaning; everything before it specifies. At the seam: linking -s after -ung/-heit/-keit/-schaft/-tät/-ion.

The Head Sets Gender and Plural

Remember one sentence: the last noun wins. Whether a compound is der, die or das depends only on the head noun, not on the word in front of it. Das Haus, but die Tür, gives die Haustür, because Tür stands at the end. You take the plural directly from the head noun as well.

See the pattern? The plural of the whole compound is always the plural of the head noun: Tür becomes Türen, so Haustüren. Try it right away. Find the head noun first, and the rest follows on its own.

Seams at a Glance

Between the modifier and the head noun there is sometimes a small connector, the seam. In the C-test this is pure gold: if the gap falls exactly on the seam, you only need to know which connector is usual here. The table below shows all the seams you need for the onSET.

The two most common seams in the onSET are the linking -s- and the linking -n-. Test your instinct on two classic words.

You will now get to know both seams more closely.

Linking -s-: The Most Common Seam

A linking -s- is not just a matter of taste. It has two reliable sources. The first is the ending of the modifier: if the first word ends in -ung, -heit, -keit, -schaft, -tät, -ion, -tum or -ling, you can safely put an s at the seam.

These endings are your signal. As soon as you see one of them at the end of the first part, the gap at the seam is an s. Check it on two examples.

The second source is a group of fixed learned words. Some common nouns carry the linking -s- even though they end in none of the endings above. You do not recognize them by a rule; you learn them as whole building blocks: Arbeit, Geburt, Liebe, Hilfe.

Arbeitsplatz and Geburtstag therefore do not belong to the ending rule but to this learned group. A few of them also change their form: Hilfe drops its -e before the s (Hilfsmittel), while Liebe keeps it (Liebesbrief). Note also: Liebe and Hilfe end in -e, yet they take an s instead of the otherwise usual linking -n-. Exactly such exceptions make them learned words. These words appear often in the onSET, so memorize them as complete building blocks.

Linking -n- and Linking -e-

Besides the s there are two more seams that appear often in the onSET. The linking -n- stands with nouns ending in -e: feminine ones like Straße and Sonne, but also masculine weak nouns like der Junge or der Kollege. (Straße itself is feminine, not a weak noun; the -n- here simply follows the final -e.) The longer form -en- stands with weak nouns like der Mensch and with nouns whose plural ends in -en (die Frau → Frauen). The linking -e- shows up with some single-syllable nouns.

Watch the ending signal of the first part: if it ends in -e (Straße, Sonne), an n is very likely. Fill in the fitting seams.

Cracking the Seam in the C-Test

Now we bring it all together. In the onSET you see a half-deleted compound and complete the second half. Two questions lead you safely to the goal: what is the head noun (that gives the article and the plural)? And which seam joins the parts? The decompositions below show the way.

Walk through one such decomposition yourself. Determine the article via the head first, then the seam, then the plural.

The head noun Zeit is feminine, so die Arbeitszeit. Arbeit is one of the fixed learned words that take a linking -s- (like Geburt and Hilfe), hence Arbeitszeit. The plural follows Zeit: Zeiten, so Arbeitszeiten. Three small steps, one certain answer.

Quick Decision

When a compound stands in front of you in the C-test, run through this list:

1. Find the head noun. The last noun is the head. It supplies gender and plural. (die Haustür → head Tür → die)
2. Take the article and plural. Both come straight from the head. (plural of Tür is Türen → Haustüren)
3. Check the seam: linking -s-? If the modifier ends in -ung, -heit, -keit, -schaft, -tät, -ion, -tum or -ling, there is an s. Fixed learned words like Arbeit, Geburt or Hilfe also take an s.
4. Check the seam: linking -n-? If the modifier is a weak noun or ends in -e, there is often -n- or -en-.
5. Otherwise usually no seam. If none of that applies, the parts are joined without a connector (Tischbein, Fußball).

Common Mistakes

1. Gender from the wrong part. das Haus, but die Haustür. The head noun Tür decides, not Haus. „das Haustür“ would be wrong.
2. Forgetting the linking -s-. After -ung, -heit and the like, an s belongs there. „Meinungfreiheit“ is wrong, the correct form is Meinungsfreiheit.
3. One linking -s- too many. Not every seam needs an s. „Tischsbein“ is wrong, the correct form is Tischbein.
4. Plural from the wrong part. The plural lives in the head. Arbeitsplatz becomes Arbeitsplätze (Platz → Plätze), not „Arbeitsplatzen“.

Boss gap

Six seams in one gap, and one of them breaks the rule outright: this drill stacks linking-s, linking-n, and the seamless exception together. Type what is missing at the joint: an s, an n, or no linking element at all. Careful: for the seamless word the gap covers the beginning of the head word, so simply fill in its missing letters.

Related reading: suffixes and prefixes are in "Word Formation: Suffixes", vocabulary topic fields in "Vocabulary Strategy", and fixed word pairs in "Collocations and FVG".