Learn Hardcore Greek: Το παράθυρο που κλείνεις είναι μικρό. - The window that you are closing is small.

που introduces a relative clause and means “that/which/who” in English. It links the noun το παράθυρο to the clause κλείνεις, restricting which window we’re talking about. It’s the standard, everyday way to form relative clauses in Modern Greek and it does not change for gender, number, or case (it’s invariable).

How is που different from πού?

που (no accent) = relative/conjunction: “that/which/who.”
- Example: Το παράθυρο που κλείνεις…
πού (with an accent) = interrogative/exclamative “where?”
- Example: Πού κλείνεις το παράθυρο;

They’re pronounced the same in continuous speech, but the accent mark distinguishes the meanings in writing.

Why is it μικρό and not μικρός or μικρή?

Because adjectives agree in gender, number, and case with the noun they describe. παράθυρο is neuter singular nominative, so the adjective is neuter singular nominative: μικρό.

Basic forms: masculine μικρός, feminine μικρή, neuter μικρό.
Plural: masculine μικροί, feminine μικρές, neuter μικρά.

Why is there no explicit “you” before κλείνεις?

Greek usually drops subject pronouns because the verb ending shows the person and number. The ending -εις in κλείνεις already tells you it’s “you” (2nd person singular). You can add εσύ for emphasis or contrast: Εσύ κλείνεις το παράθυρο, όχι εγώ.

What tense/aspect is κλείνεις, and how would I express past or future?

κλείνεις is present indicative, imperfective aspect. It can be “you close” (habitual) or “you are closing” (right now).
Completed past (aorist): που έκλεισες.
Ongoing past (imperfect): που έκλεινες (e.g., “that you were closing”).
Future: που θα κλείσεις.
To make the ongoing sense explicit, add a time word: που κλείνεις τώρα (“that you’re closing now”).

Why is Το παράθυρο in the nominative if it’s the thing being closed?

Because in the main clause it’s the subject of είναι (“is”), so it’s nominative: Το παράθυρο … είναι μικρό. Inside the relative clause, the understood element is the object of κλείνεις, but που doesn’t show case. If you use the more formal relative ο οποίος, the relative pronoun reflects the object role: Το παράθυρο το οποίο κλείνεις είναι μικρό.

Can I omit που like English often omits “that”?

No. Greek requires a relativizer. Without it the sentence is ungrammatical.

Wrong: Το παράθυρο κλείνεις είναι μικρό.
Right: Το παράθυρο που κλείνεις είναι μικρό.

Can I use ο οποίος/η οποία/το οποίο instead of που? What’s the difference?

Yes. It’s more formal and declines for gender, number, and case:

Το παράθυρο το οποίο κλείνεις είναι μικρό. In everyday speech and writing, που is far more common; ο οποίος sounds formal, legalistic, or emphatic.

Do I need a comma before που κλείνεις?

No. This is a restrictive relative clause (it specifies which window), so no comma. A comma would mark a non‑restrictive clause, which would be unusual here and would change the meaning to an aside: Το παράθυρο, που κλείνεις, είναι μικρό (“the window, which you are closing, is small”)—not typical in this context.

How do I pronounce the tricky parts?

παράθυρο: [paˈraθiro] (θ like English “th” in “think”).
κλείνεις: [ˈklinis] (ει = [i]; final -εις = [is]).
είναι: [ˈine] (ει = [i]; αι here yields [e], but the whole word is [ˈine]).
που: [pu] (like “poo” in “pool”).
μικρό: [miˈkro] (stress on the last syllable). The written accent marks show the stressed syllable: παράθυρο, κλείνεις, είναι, μικρό.

Why is it είναι and not είσαι?

Because the subject is το παράθυρο (3rd person singular). είναι is the 3rd person form; είσαι is 2nd person (“you are”).

Can I say Το παράθυρο είναι μικρό που κλείνεις?

Not for this meaning. Greek doesn’t allow the relative clause to drift away from the noun like that. Keeping the clause right after the noun is the normal pattern: Το παράθυρο που κλείνεις είναι μικρό. Note: Greek also uses που as a complementizer after evaluative expressions (e.g., Είναι καλό που το κλείνεις = “It’s good that you’re closing it”), but that’s a different structure.

Should I add a direct object clitic inside the relative clause (που το κλείνεις)?

Standardly, no—the antecedent (το παράθυρο) is understood as the object of κλείνεις, so you don’t repeat it. In colloquial Greek, a resumptive clitic can appear for emphasis or clarity: Το παράθυρο που το κλείνεις κάθε βράδυ… This is common with prepositional or genitive objects; with direct objects it’s heard but best avoided in careful speech unless you want that colloquial flavor.

How does the sentence change in the plural?

Τα παράθυρα που κλείνεις είναι μικρά. Changes:
Article/noun to neuter plural: τα παράθυρα.
Predicate adjective to neuter plural: μικρά.
είναι stays the same in the 3rd person (it’s both singular and plural).
κλείνεις stays 2nd person singular; you’re still the one closing them.

How would I say it with an attributive adjective instead of a predicate adjective?

Put the adjective directly before the noun: Το μικρό παράθυρο που κλείνεις … Example continuation: Το μικρό παράθυρο που κλείνεις είναι καινούριο. Here, μικρό is attributive (part of the noun phrase), not the predicate.

What’s the difference between που κλείνεις and που κλείνει?

που κλείνεις = “that you close/are closing” (2nd person singular).
που κλείνει = “that he/she/it closes” or “that closes” (3rd person). Example: Το παράθυρο που κλείνει μόνο του = “the window that closes by itself.”

Is the article το necessary? Can I say Παράθυρο που κλείνεις είναι μικρό or use ένα?

You cannot drop the article here; Παράθυρο που κλείνεις… is ungrammatical in standard Greek.
You can use the indefinite article ένα for a non‑specific reference: Ένα παράθυρο που κλείνεις είναι μικρό, but that means “a (certain) window that you are closing is small” and sounds odd unless the context really calls for an indefinite, non‑specific mention. Usually, with a specifying relative clause, Greek prefers the definite article το.