Learn Hardcore Greek: Το δοκιμαστήριο σε αυτό το κατάστημα είναι καθαρό και αρκετά μεγάλο. - The fitting room in this store is clean and quite big.

Its dictionary form is δοκιμαστήριο (το).
το shows that it is neuter in Greek.
So any adjective referring to it (like καθαρό, μεγάλο) will also be neuter singular to agree with it.

Why is it το δοκιμαστήριο and not something like η δοκιμαστήριο?

Because δοκιμαστήριο is a neuter noun, it always takes the neuter article:

Nominative singular: το δοκιμαστήριο – the fitting room
Genitive singular: του δοκιμαστηρίου – of the fitting room
Accusative singular: το δοκιμαστήριο – the fitting room (object)

If it were feminine, it would take η; if masculine, ο. Here, it is neuter, so το is correct.

Why is καθαρό neuter? I would expect something like καθαρός or καθαρή.

In Greek, adjectives must agree in gender, number, and case with the noun they describe.

Noun: το δοκιμαστήριο → neuter, singular, nominative
Adjectives describing it:
- καθαρό (clean) → neuter, singular, nominative
- μεγάλο (big) → neuter, singular, nominative

Forms like καθαρός (masculine) or καθαρή (feminine) would agree with masculine or feminine nouns, not with a neuter like δοκιμαστήριο. So το δοκιμαστήριο είναι καθαρό is grammatically correct.

What does αρκετά mean here in αρκετά μεγάλο? Why not just μεγάλο?

αρκετά here is an adverb that modifies the adjective μεγάλο.

μεγάλο alone = big
αρκετά μεγάλο = quite big, fairly big, big enough

So the phrase καθαρό και αρκετά μεγάλο means “clean and quite big” (or clean and big enough), adding nuance to the size.

Note: αρκετά can also be a plural neuter adjective (e.g. αρκετά παιδιά = enough children), but in this sentence it is an adverb.

Why is it σε αυτό το κατάστημα and not just στο κατάστημα?

Both are correct but they mean slightly different things:

στο κατάστημα = in the store (general, just “the store”)
σε αυτό το κατάστημα = in this store (specifically “this store [here / that we’re talking about]”)

In σε αυτό το κατάστημα:

σε = in / at
αυτό = this (neuter, to agree with κατάστημα)
το κατάστημα = the store

So the full phrase literally corresponds to “in this the store”, but in natural English it’s “in this store”.

Why does Greek say σε αυτό το κατάστημα with both αυτό and το? In English we just say “this store” without “the”.

This is a structural difference between Greek and English.

In Greek, when you use a demonstrative (this/that), you almost always keep the definite article as well:

αυτό το κατάστημα = this store
εκείνο το κατάστημα = that store

English usually drops “the” in this situation (“this store”, not “this the store”), but Greek keeps:

demonstrative (αυτό)
- article (το)
- noun (κατάστημα)

So σε αυτό το κατάστημα follows that normal pattern: preposition + demonstrative + article + noun.

Can σε αυτό το be contracted? I’ve seen σ’ αυτό το or στο – what’s the difference?

Yes, in spoken and written Greek there are common contractions:

σε αυτό το κατάστημα
- Fully written out, slightly more formal or careful.
σ’ αυτό το κατάστημα
- σε
  - vowel-starting word (αυτό) → σ’ αυτό in speech and often in writing.
- Very common and perfectly standard.
στο κατάστημα
- σε
  - το → στο
- This means “in the store”, not “in this store” (the demonstrative αυτό is missing).

So:

σ’ αυτό το κατάστημα = in this store
στο κατάστημα = in the store (no “this”)

Could I change the word order to Το δοκιμαστήριο είναι καθαρό και αρκετά μεγάλο σε αυτό το κατάστημα?

You can move phrases around in Greek, but you must be careful with clarity and emphasis.

Το δοκιμαστήριο σε αυτό το κατάστημα είναι καθαρό και αρκετά μεγάλο.
→ Neutral, natural: “The fitting room in this store is clean and quite big.”
Το δοκιμαστήριο είναι καθαρό και αρκετά μεγάλο σε αυτό το κατάστημα.
→ Grammatically possible, but it can sound a bit awkward.
→ It may be interpreted as: “The fitting room is clean and quite big in this store (as opposed to other stores).”

In practice, the original order with σε αυτό το κατάστημα right after το δοκιμαστήριο is more natural and clearer.

What verb form is είναι, and does it have to be there?

είναι is the 3rd person singular present tense of the verb είμαι (to be).

είμαι = I am
είσαι = you are
είναι = he/she/it is OR they are (context decides)

In the sentence:

Το δοκιμαστήριο … είναι καθαρό και αρκετά μεγάλο.
→ “The fitting room … is clean and quite big.”

Yes, είναι is required in standard Greek. Unlike some other languages, you generally cannot omit the verb “to be” in the present tense in this kind of sentence.

Why are καθαρό and μεγάλο both neuter singular? Do both adjectives refer to το δοκιμαστήριο?

Yes, both adjectives describe το δοκιμαστήριο, so they must both:

match its gender → neuter
match its number → singular
match its case → nominative

So we get:

το δοκιμαστήριο (neuter, singular, nominative)
- καθαρό (neuter, singular, nominative)
- μεγάλο (neuter, singular, nominative)

The και links two adjectives describing the same noun:
καθαρό και αρκετά μεγάλο = clean and quite big.

How do you pronounce the longer words like δοκιμαστήριο, κατάστημα, and αρκετά?

The written accent marks the stressed syllable:

δοκιμαστήριο → do-ki-ma-STI-ri-o
- Stress on στή
κατάστημα → ka-TA-sti-ma
- Stress on τά
αρκετά → ar-ke-TA
- Stress on τά

In Greek, each word has one main stress, and pronouncing it correctly is important for understanding.

What are the plurals of δοκιμαστήριο and κατάστημα, and how would the adjectives change in the plural?

Both nouns are neuter, so their plurals are:

το δοκιμαστήριο → τα δοκιμαστήρια (fitting rooms)
το κατάστημα → τα καταστήματα (stores/shops)

If you made the whole phrase plural:

Τα δοκιμαστήρια σε αυτά τα καταστήματα είναι καθαρά και αρκετά μεγάλα.
- τα δοκιμαστήρια (neuter plural)
- σε αυτά τα καταστήματα (in these stores)
- είναι (they are)
- καθαρά (clean – neuter plural)
- μεγάλα (big – neuter plural)

Notice how the adjectives change to καθαρά, μεγάλα to agree with the neuter plural noun δοκιμαστήρια.