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Questions & Answers about Das Fenster ist aus Glas.
Why is Fenster preceded by das?
Fenster is a neuter noun in German. In the nominative singular, the definite article for neuter nouns is das.
Why is there no article before Glas in aus Glas?
When you express that something is made of a material, German typically uses aus + [Material] without an article. If you added an article (e.g. aus dem Glas), you’d imply “out of a specific glass container,” not “made of glass” in general.
Which case does aus require, and why don’t we see it on Glas?
The preposition aus always takes the dative case. Mass nouns like Glas don’t show visible endings when used without an article, so Glas looks the same even though it’s in the dative. If you included the article, you’d say aus dem Glas.
Could I say Das Fenster ist gläsern instead of aus Glas?
Yes. gläsern is a predicate adjective meaning “made of glass.” So Das Fenster ist gläsern is grammatically correct, though everyday German more often uses aus Glas to state the material.
What’s the difference between aus Glas and gläsern?
aus Glas is a prepositional phrase focusing on material (“of glass”). gläsern is an adjective form. You can use it predicatively (ist gläsern) or attributively (e.g. ein gläsernes Fenster), but attributive use requires the correct adjective ending.
Can I change the word order to Aus Glas ist das Fenster?
You can, but it sounds marked or poetic. The neutral, everyday word order is Subject–Verb–Prepositional Phrase: Das Fenster ist aus Glas.
How do I know Glas here means “glass” (material) and not “a drinking glass”?
Context and the absence of an article mark the material sense. A drinking vessel would need an article or number (ein Glas, zwei Gläser). aus Glas without article means “made of glass.”
If I talk about multiple windows, does aus Glas change?
No. You’d say Die Fenster sind aus Glas. The prepositional phrase stays the same in singular and plural.
Why is Fenster capitalized in the middle of the sentence?
In German, all nouns are always capitalized, no matter where they appear in a sentence.
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“How do German cases work?”
German has four grammatical cases: nominative (subject), accusative (direct object), dative (indirect object), and genitive (possession). The case determines the form of articles and adjectives. For example, "the dog" is "der Hund" as a subject but "den Hund" as a direct object.
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