Compound words (Zusammensetzung)

Compound words are formed by joining two or more self-standing words into a single one. Different parts of speech can be used.
Parts of speechCompound word
Noun + NounGartenhaus
Verb + NounReithalle
Adjective + NounHochhaus
Prepostion + NounAufstand
Verb + Adjectivetreffsicher
Noun + Adjectivesteinreich
Preposition + Adjectiveüberdeutlich
Adjective + Verbhellsehen
Noun + Verbteilnehmen
Preposition + Verbunterschlagen
As you can see from the table nouns are very common in these combinations.
Compound words from verbs + other words
If the verb is in the first place in a compound word, the -en / -n ending of the infinitive is omitted. Only the stem of the verb is used:
treffen + sicher -> treffsicher
gehen + Weg -> Gehweg

Linking elements

Sometimes, words are joint together using a linking element between them. Their role is the make the pronunciation easier. However, there isn't a formal rule establishes when they are used.
One particular situation in which linking elements are used is when the first word of the compound is a noun. Most often 's' is used, however, you can also encounter 'e', 'es', 'en', 'ens', 'n', 'er' etc.
Examples:
Arbeitszimmer, gebrachsfertig, Zahlungsziel, Schmerzensgeld

Primary words, determiners

When compounding words, we differentiate between the determiner and the primary word:
Wasser (determiner) + Glas (primary word) -> Wasserglas
The basic word always determines the part of speech of the compound, while the determiner gives more specific information about the word.

The primary word

The primary word is always the last component of a compound (the rightmost part) and it determines all the grammatical features of the word, including the part of speech. When the primary word is a noun, its gender is also the gender of the compound.
Determiner(s) + primary wordCompound word (Part of speech)
reiten + Halle (Verb stem + noun)Reitenhalle (Noun)
auf + Stand (preposition + noun)Aufstand (Noun)
Teil + nehmen (noun + verb)teilnehmen (verb)

The determiner can describe:

  • a characteristic : Gehweg (a path on which people walk)
  • a comparison: taghell (lit as much as a day)
  • a purpose, characteristic : Schreibtisch (a table on which people write)
  • a reason : Gasexplosion

Keep in mind that compounds can be formed with more than one determiner, and they can also accept prefixes and suffixes.