In short

Greek has two everyday pointing words: αυτός for what is near (“this”) and εκείνος for what is far (“that”). They inflect like ordinary adjectives in -ος, -η, -ο, and they agree with their noun in gender, number and case.

The one thing that surprises English speakers is the article. English says this book with no article; Greek keeps the definite article and puts the demonstrative outside it: αυτό το βιβλίο (or το βιβλίο αυτό), never αυτό βιβλίο, and never το αυτό βιβλίο.

The very same words do a second job with no article at all: they are the strong third-person pronouns, “he / she / it / they” when you need to stress, contrast or point. Αυτός είναι ο Νίκος. Εκείνον ξέρω.

The rule

1. Agreement. The demonstrative copies the noun’s gender, number and case: αυτός ο φίλος, αυτή η φίλη, αυτό το παιδί, αυτούς τους φίλους.
2. The article is obligatory and the demonstrative stands outside it. Two orders are possible and both are normal: αυτό το βιβλίο (neutral) and το βιβλίο αυτό (a little more emphatic, common in writing). What is impossible is the article-less αυτό βιβλίο and the sandwich το αυτό βιβλίο (the learned ο αυτός / το αυτό does exist, but it means “the same”, not “this”).
3. Case runs through all three words. Once the phrase is an object, every element moves to the accusative: Ξέρω αυτόν τον άντρα. Βλέπω εκείνα τα παιδιά.
4. Near and far pair up with the place adverbs εδώ “here” and εκεί “there”: αυτό εδώ ↔ εκείνο εκεί. Adding the adverb is the usual way to make the contrast visible.
5. Same words, no article = pronoun. Standing alone, αυτός/αυτή/αυτό and εκείνος/εκείνη/εκείνο replace a noun phrase and serve as the strong third-person pronouns of lesson 10: Αυτή είναι η δασκάλα μου. Εκείνους δεν τους ξέρω.
6. Genitive forms exist (αυτού, αυτής, αυτών) and are shown below for completeness, but the genitive case as a system waits for lesson 31. At A1 you need the nominative and the accusative.

Forms & patterns

αυτός, αυτή, αυτό — “this” (near)

Singular:

Plural:

Demonstratives have no vocative — you point at things, you do not call them.

εκείνος, εκείνη, εκείνο — “that” (far)

Singular:

Plural:

The feminine accusative αυτή(ν) / εκείνη(ν) follows the final -ν rule of lesson 8: the -ν is normally written when the word stands alone as a pronoun (Εκείνην είδα) and before a vowel or κ, π, τ, μπ, ντ, γκ, τσ, τζ, ξ, ψ.

The whole phrase: demonstrative + article + noun

This is the pattern to memorise as one block.

εκείνος behaves identically: εκείνη η γυναίκα, εκείνην τη γυναίκα, εκείνες οι γυναίκες, εκείνες τις γυναίκες.

The postposed order simply moves the demonstrative behind the noun, article included: το παιδί αυτό, η γυναίκα εκείνη, τα βιβλία αυτά.

τέτοιος and τόσος

τέτοιος “such, this/that kind of” and τόσος “so much, so many” are demonstratives of quality and of quantity. They inflect like adjectives too (τέτοιος keeps the feminine in -α: τέτοια, τέτοιας), but they do not take the definite article the way αυτός does: τέτοιος άνθρωπος, ένα τέτοιο σπίτι, τόσος κόσμος.

Να — the pointing word

να (not the να of να + subjunctive) presents something on the spot, like French voilà: Να ο Γιάννης! Να το σπίτι μας! With a weak pronoun it makes the short forms Να τος! “There he is!”, Να τη!, Να το!, Να τοι! / Να τες! / Να τα!

τούτος — recognition only

τούτος, τούτη, τούτο is an emphatic “this one right here”, much less common than αυτός and at home in colloquial speech, songs, proverbs and set phrases (τούτο εδώ, τούτη τη φορά κι όχι την άλλη). Recognise it; say αυτός.

Examples

Common mistakes

• αυτό βιβλίο -> αυτό το βιβλίο — the article never drops; Greek says literally “this the book”.
• το αυτό βιβλίο -> αυτό το βιβλίο / το βιβλίο αυτό — the demonstrative stands outside the article, never between article and noun.
• εκείνο η γυναίκα -> εκείνη η γυναίκα — the demonstrative takes the noun’s gender, so a feminine noun needs the feminine form.
• Αυτό είναι η δασκάλα -> Αυτή είναι η δασκάλα — pointing at a person, the pronoun takes that person’s gender; neuter αυτό is for things and ideas (Αυτό είναι το πρόβλημα).
• Ξέρω αυτός ο άντρας -> Ξέρω αυτόν τον άντρα — an object puts all three words in the accusative, not just the noun.
• αυτά τα καρέκλες -> αυτές οι καρέκλες — gender and case must match right across the phrase, article included.
• Αυτό τα βιβλία -> Αυτά τα βιβλία — number agreement: plural noun, plural demonstrative.
• ο τέτοιος άνθρωπος -> τέτοιος άνθρωπος / ένας τέτοιος άνθρωπος — τέτοιος does not take the definite article the way αυτός does.

Tips

• Learn the phrase, not the word: drill αυτό το + neuter noun, αυτή η + feminine noun, αυτός ο + masculine noun as three fixed blocks. The article is part of the demonstrative for you.
• The endings are exactly those of an adjective in -ος, -η, -ο, so anything you know about καλός, καλή, καλό transfers straight over — including the accusative -ν on αυτόν, εκείνον.
• Pin each word to its adverb: αυτός goes with εδώ, εκείνος goes with εκεί - and the far pair carries its mnemonic in the spelling.
• With no article after it, the demonstrative is a pronoun; with an article after it, it is a modifier. That single test tells you which job the word is doing in the sentence.
• When you identify a person, let the pronoun agree with the person, not with the English “this”: Αυτή είναι η Μαρία, αυτός είναι ο Κώστας.
• In a shop or at a market you can survive on the neuter alone: Αυτό, παρακαλώ. Πόσο κάνει εκείνο; Θέλω αυτά εδώ.
• Do not worry about the genitive αυτού / αυτής / αυτών yet — you will hardly need it before lesson 31.