In short

Greek has one definite article, but it changes shape: it agrees with its noun in gender (masculine, feminine, neuter), number (singular, plural) and case (nominative, genitive, accusative). That gives twelve little words in all, and several of them repeat, so the real memory load is small: ο, η, το in the singular and οι, οι, τα in the plural, plus του/της/των and τον/την/τους/τις.

The second half of the lesson is about where the article goes, and there Greek is far more generous than English. Greek says “the Maria”, “the Greece”, “the Mr Papadopoulos”, “the love”, “the coffee”. Wherever English drops the article - before first names, countries, titles, abstract nouns, whole categories - Greek normally keeps it. Leaving it out is one of the most audible beginner mistakes.

The rule

Agreement. The article carries the grammatical information; the noun follows. Because the article is short and highly frequent, it is what a listener uses to work out gender and case. Learn every new noun together with its nominative article - not σπίτι but το σπίτι, not θάλασσα but η θάλασσα. The article is the gender tag.

Three cases only. Modern Greek nominals have four cases, but the article appears in only three of them: ονομαστική (nominative, the subject), γενική (genitive) and αιτιατική (accusative, the direct object and the case after prepositions). The fourth case, the κλητική (vocative, used for calling someone), takes no article at all: you say «Γιώργο!», «κύριε Παπαδόπουλε!», never ο Γιώργο. And there is no dative in Modern Greek, so no dative article either - forget any ancient dative forms you may have met.

Shared shapes. Notice the economies: the genitive singular is του for both masculine and neuter; the neuter has the same form το (sg.) and τα (pl.) for nominative and accusative; the nominative plural is οι for both masculine and feminine; and the genitive plural is των for all three genders. Five forms do double duty (το, του, οι, των, τα); the other seven - ο, η, της, τον, την, τους, τις - each point to a single slot.

The article on names and countries. Personal names are ordinary nouns in Greek and take the article in normal sentences: η Μαρία, ο Γιώργος. Countries, regions and most cities do too, each with a fixed gender you simply learn: η Ελλάδα, η Ιταλία, ο Καναδάς, το Μεξικό, η Αθήνα, το Λονδίνο. Titles behave the same way when you talk about someone: ο κύριος Παπαδόπουλος, η κυρία Ιωάννου.

The article on generics and abstracts. When a noun stands for a whole class or an abstract idea, Greek uses the article where English uses nothing: η αγάπη “love”, ο χρόνος “time”, ο καφές “coffee” (as a thing you like in general), τα ελληνικά “Greek (the language)”. English “Coffee is expensive” is «Ο καφές είναι ακριβός».

Forms & patterns

The full grid. All twelve forms are monosyllables, so none of them carries an accent - with one caution: the feminine η is spelled without an accent, while the accented ή is the word “or”.

The same grid with a noun in place, so you can hear the rhythm. (The noun endings themselves are the next lesson’s business; note only that the stress can move, as in ο άνθρωπος → του ανθρώπου.)

A stress shift in a longer masculine noun, for comparison:

Where English uses no article and Greek does:

Examples

Common mistakes

• Μαρία είναι δασκάλα. -> Η Μαρία είναι δασκάλα. First names keep the article in ordinary sentences; only when you call out to her does it disappear («Μαρία!»).
• Είμαι από Ελλάδα. -> Είμαι από την Ελλάδα. Country names take the article, and after the preposition από it goes into the accusative.
• ο Ελλάδα, ο Ιταλία -> η Ελλάδα, η Ιταλία. Country names have a fixed gender that has nothing to do with English; learn each one with its article, as with any noun.
• Καλημέρα, ο κύριε Παπαδόπουλε. -> Καλημέρα, κύριε Παπαδόπουλε. No article in the vocative - but you do say «Ο κύριος Παπαδόπουλος είναι εδώ» when talking about him.
• Βλέπω της φίλες μου. -> Βλέπω τις φίλες μου. της is feminine singular genitive; the feminine plural accusative is τις. They sound alike, so check number and case.
• Ρωτάω τις φίλους μου. -> Ρωτάω τους φίλους μου. In the accusative plural the genders split: τους for masculine, τις for feminine, τα for neuter.
• Ξέρω ο Παύλος. -> Ξέρω τον Παύλο. A direct object goes into the accusative, and the article changes with it: ο → τον.
• Αγάπη είναι δυνατή. -> Η αγάπη είναι δυνατή. Abstract nouns used as a general idea take the article, unlike English.
• Μιλάω ελληνικά πολύ καλά - ελληνικά είναι δύσκολα. -> … τα ελληνικά είναι δύσκολα. After μιλάω the bare form is fine (“I speak Greek”), but as the subject of a sentence the language name needs τα.

Tips

• Memorise the grid in rows, not cells: ο - η - το, του - της - του, τον - την - το, then οι - οι - τα, των - των - των, τους - τις - τα. Six short chants cover the whole system.
• Two shortcuts worth trusting: the genitive plural is always των, and the neuter never distinguishes nominative from accusative (το / τα for both).
• Store every new noun as article + noun (η θάλασσα, το τραπέζι, ο ουρανός). A noun learned without its article is a noun whose gender you will guess wrong later.
• Watch η against ή: the article is bare, the word for “or” is accented. «Η Άννα ή η Ελένη;»
  • “Anna or Eleni?”
• Default to inserting the article whenever English omits it. If you translate “I like coffee” word for word you get μου αρέσει καφές, which sounds unfinished; Greek wants «Μου αρέσει ο καφές».
• When a weak possessive follows a word stressed on its third-from-last syllable, add the second accent: ο δάσκαλός μου, το αυτοκίνητό του, το μάθημά μας. The article itself never takes an accent.
• If you are unsure of a country’s gender, the ending is a fair guide: most are feminine, above all those in -ία (η Γαλλία, η Γερμανία, η Ισπανία), a few masculine (ο Καναδάς), a few neuter (το Βέλγιο, το Μεξικό). It is a tendency, not a rule, so learn each country with its article.