Hún vinnur í stóru fyrirtæki í miðbænum.

Í governs:

• the dative for location (where something is): í miðbænum = in the city center (dative, definite)
• the accusative for motion (into/onto): í miðbæinn = into the city center (accusative, definite)

Compare:

• Static: Hún vinnur í miðbænum.
• Motion: Hún fer í miðbæinn.

With the company:

• Static: í fyrirtækinu (in/at the company, dative)
• Motion: í fyrirtækið (into the company building, accusative)

Because after í (location), the noun phrase is in the dative, and the adjective must agree. For the adjective stór in neuter singular:

• Nominative/accusative (indef.): stórt fyrirtæki
• Dative (indef.): stóru fyrirtæki

So we get í stóru fyrirtæki (in a big company). If the phrase were definite, the adjective would take the weak ending: í stóra fyrirtækinu (in the big company).

Fyrirtæki is neuter. In the singular, its nominative, accusative, and dative forms are all fyrirtæki (no change). The genitive singular is fyrirtækis. Plural forms include:

• Nominative/accusative plural: fyrirtæki
• Dative plural: fyrirtækjum So here, í stóru fyrirtæki is dative singular neuter (indefinite), with the adjective showing the case.

It’s the suffixed definite article in the dative singular for masculine nouns. Base noun: miðbær (city/town center).

• Indefinite dative: í miðbæ = in a city center
• Definite dative: í miðbænum = in the city center (i.e., downtown) The article is attached to the noun (Icelandic has no separate “the” word in most cases).

Yes, but the nuance changes:

• vinna hjá
  • company = work for/be employed by that company: Hún vinnur hjá stóru fyrirtæki.
• vinna í
  • place = work in/at a place (physical location or environment): Hún vinnur í stóru fyrirtæki. Both are common; hjá is more explicit about the employer, while í emphasizes the workplace as a location.

Icelandic has no separate word for the indefinite article “a”. Indefinite is just nothing: í stóru fyrirtæki = in a big company. The definite article “the” is a suffix on the noun:

• Nominative: fyrirtækið = the company
• Dative: fyrirtækinu = in the company With a definite adjective, the adjective takes weak endings: í stóra fyrirtækinu = in the big company.

Use the progressive with vera að:

• Hún er að vinna. = She is working (now). To include employer/place:
• Hún er að vinna hjá stóru fyrirtæki í miðbænum. The simple present Hún vinnur … is typically habitual or general.

Stacked location phrases often go from more specific to broader: workplace first, then the area. You can swap for emphasis or style:

• Hún vinnur í miðbænum, í stóru fyrirtæki.
• Í miðbænum vinnur hún í stóru fyrirtæki. All are grammatical; word order is fairly flexible for information structure.

Use the dative plural for both adjective and noun:

• Hún vinnur í stórum fyrirtækjum í miðbænum. Here, stórum (adj.) and fyrirtækjum (noun) are dative plural.

Both exist:

• miðbær = town/city center (very common in everyday speech, even in cities)
• miðborg = city center (more formal/technical) Definite datives: í miðbænum, í miðborginni. In Reykjavík you’ll see both; miðbær is extremely common in conversation.

Yes. starfar is a common, more formal/literary choice meaning “works/is employed”:

• Hún starfar hjá stóru fyrirtæki í miðbænum. It emphasizes professional employment a bit more than everyday vinnur.