Learn Hardcore German: Im Flur hängt ein neuer Spiegel, in dem ich morgens mein Outfit prüfe. - In the hallway hangs a new mirror in which I check my outfit in the morning.

Im Flur is the normal, neutral everyday form.
In dem Flur sounds heavier and is usually only used if you want to contrast or specify a particular hallway (for example, In dem Flur links hängt ein Spiegel, im rechten nicht.).

The case is dative because in with a static location (no movement) takes the dative:
der Flur → dem Flur → im Flur.

What exactly is Flur? Is it the same as Korridor or Gang?

In this context, Flur is a hallway or corridor inside a flat or house.

Nuances:

Flur – very common in everyday German for the hallway in an apartment or house.
Korridor – also a corridor, often sounds a bit more formal or institutional (offices, schools, hotels).
Gang – used more in southern Germany, Austria, Switzerland; also means corridor/hallway.

In this sentence, Im Flur is the most natural way to say in the hallway in standard German.

Why is the verb hängt used instead of ist?

hängen is the verb you use for things that are hanging on a wall, hook, etc.

Im Flur hängt ein neuer Spiegel = The mirror is physically hanging (attached) on the wall.
Im Flur ist ein neuer Spiegel would be understood, but it focuses more on simple existence (there is a new mirror in the hall) and sounds a bit less specific.

Native speakers strongly prefer hängt when the object is on the wall:
An der Wand hängt ein Bild / Spiegel / Poster.

Why is the word order Im Flur hängt ein neuer Spiegel and not Ein neuer Spiegel hängt im Flur?

Both sentences are correct German. The difference is emphasis:

Im Flur hängt ein neuer Spiegel.
Puts the hallway (Im Flur) in the first position. You are talking about what is in the hallway.
Ein neuer Spiegel hängt im Flur.
Puts ein neuer Spiegel in first position. You are introducing the mirror as the main topic, then adding where it hangs.

German main clauses follow the verb-second rule: the finite verb (hängt) must be in second position, but almost any one element (subject, time, place, etc.) can occupy the first position:

Im Flur | hängt | ein neuer Spiegel.
Ein neuer Spiegel | hängt | im Flur.

So the change is about focus, not correctness.

Why is there a comma before in dem ich morgens mein Outfit prüfe?

Because in dem ich morgens mein Outfit prüfe is a subordinate clause, more specifically a relative clause describing der Spiegel.

German rules require a comma before:

relative clauses (introduced by der, die, das, welcher, welche, welches, or wo when used relatively),
and most other subordinate clauses (weil, dass, wenn, etc.).

So the comma before in dem is obligatory: it marks the beginning of a clause that gives extra information about the mirror.

What is the function of in dem here? Why not just der or wo?

in dem is preposition + relative pronoun, and together they mean in which:

… ein neuer Spiegel, in dem ich morgens mein Outfit prüfe.
→ … a new mirror, in which I check my outfit in the morning.

Why not der alone?

der as a relative pronoun would be a subject (who/which) or object without a preposition.
But in the clause, you need the idea in which, so the preposition in must stay with its object: in dem.

Why not wo?

You can say colloquially:
…ein neuer Spiegel, wo ich morgens mein Outfit prüfe.
This is common in speech but is considered less formal / less standard than in dem.
In careful written German, in dem (or in welchem) is preferred.

Why is it dem and not den or der in in dem?

Because dem is the dative singular masculine form of the relative pronoun, and that is what is required here.

The antecedent is Spiegel, which is:
- gender: masculine
- number: singular
- nominative in the main clause: ein neuer Spiegel hängt …
In the relative clause, dem is governed by the preposition in. Here in expresses location (no movement), so it takes the dative case.

So we need:

masculine
singular
dative

That combination gives dem:

Nominative: der (mask.)
Accusative: den (mask.)
Dative: dem (mask./neut.)

Therefore: in dem (Spiegel) → in dem.

Why does the verb prüfe come at the end in in dem ich morgens mein Outfit prüfe?

Because this is a subordinate clause (a relative clause), and German subordinate clauses normally have the finite verb at the end.

Pattern:

Main clause: verb in 2nd position
Im Flur | hängt | ein neuer Spiegel.
Subordinate clause: verb at the end
…, in dem | ich morgens mein Outfit | prüfe.

This verb-final word order is one of the key features of German subordinate clauses, no matter what comes before it in the clause.

Why is morgens placed after ich and not at the end (ich mein Outfit morgens prüfe)?

The neutral order inside a clause is typically:

Subject – Time – Object – (other stuff) – Verb (in subordinate clauses at the end)

So:

ich (subject)
morgens (time)
mein Outfit (object)
prüfe (verb at the end in a subordinate clause)

→ in dem ich morgens mein Outfit prüfe

Other orders like … in dem ich mein Outfit morgens prüfe are possible and not wrong, but they may sound a bit marked (different rhythm or emphasis). ich morgens mein Outfit prüfe is the default, most natural order.

What is the difference between morgens and am Morgen?

morgens is an adverb meaning in the mornings / in the morning (as a habit). It usually implies repeated or habitual action:
- Ich trinke morgens Kaffee. – I drink coffee in the morning(s) (as a routine).
am Morgen literally means on the morning and usually refers to a specific morning or is a bit more concrete:
- Am Morgen nach der Party war ich müde. – On the morning after the party I was tired.

In the sentence … in dem ich morgens mein Outfit prüfe, morgens suggests this is a regular routine every morning, not just one particular morning.

Why is Outfit capitalized, but morgens is not?

Because:

Outfit is a noun, and all nouns are capitalized in German.
morgens is an adverb (a time word like abends, mittags, gestern), and adverbs are not capitalized.

So:

Outfit → capital letter.
morgens → lower-case.

Is Outfit really used in German, or is there a more “German” word?

Yes, Outfit is very common in modern German and sounds completely natural, especially in everyday and fashion-related contexts.

Other options:

Kleidung – clothes, clothing (quite general).
Klamotten – informal, roughly clothes / stuff to wear.
Look – fashion/style word, close to style / look.

In this sentence, mein Outfit sounds very normal and modern, similar to English my outfit.

Is prüfen the most natural verb here? Could I say checken or ansehen instead?

prüfen means to check / to examine, and it fits well here: you are checking whether your outfit looks okay.

Other possibilities and nuances:

… in dem ich morgens mein Outfit prüfe.
Neutral, maybe slightly on the careful/thorough side.
… in dem ich morgens mein Outfit checke.
Very colloquial (from English to check), common in speech.
… in dem ich mir morgens mein Outfit ansehe.
Literally where I look at my outfit; also natural, a bit more descriptive.
… in dem ich morgens mein Outfit kontrolliere.
Feels more technical/formal; less likely for clothing in everyday speech.

So prüfen is fine and idiomatic, but learners will also hear mein Outfit checken in casual conversations.

Why is it ein neuer Spiegel and not der neue Spiegel?

Because ein neuer Spiegel introduces the mirror as new, not yet known information.

ein neuer Spiegel – a new mirror, one that you’re introducing into the conversation for the first time.
der neue Spiegel – the new mirror, implying that both speaker and listener already know which specific new mirror is meant (it has been mentioned or is obvious from context).

In your sentence, you are typically introducing the existence of this new mirror in the hallway, so ein neuer Spiegel is the natural choice. If you had already been talking about that mirror before, you might then refer to it as der neue Spiegel.