Why does τους mean "their" even though it is accusative?
In all the tables I have seen for the definite article, "τους" is listed as the plural masculine accusative form. The genitive form is listed as "των".
As I understand it, the genitive case is used for possession, and the accusative case is used for the object of a sentence.
But the translation of "τους" is "their", as in "This is their cat" - ie it is used to mean possession.
I'm confused. If the genitive case is used for possession, then why doesn't "των" mean their, instead of "τους"?
It's simply an exception: the accusative and genitive of unstressed 3rd person pronouns is always identical to the corresponding definite article, except for genitive plural where it's τους instead of the expected των.
Just in case you are confusing the definite article τους with the possessive pronoun τους.... Definite article: Masc. ο, του, τον, οι, των, τους / Fem. η,της,τη(ν),οι,των,τις / N. το,του,το,τα,των,τα Possesive pronoun is the same for all genders except third person singular. μου, σου, του/της/του, μας, σας, τους(all genders). That makes, Η γάτα μου (my cat) Η γάτα σου (your cat), H γάτα του (his cat) /H γάτα της (her cat) / Η γάτα του (Its cat), Η γάτα μας (our cat), Η γάτα σας (your cat), Η γάτα τους (their cat).
So... if you want to say, They love their dogs
Αγαπούν τους σκύλους τους
Hope I helped...
P.S. Ι wonder which form of third person plural do you learn? Αγαπούν, Αγαπούνε, Αγαπάν or Αγαπάνε? i.e. you learn "Ι love" as Αγαπώ or as Aγαπάω;
1.The DEFINITE ARTICLE/always the or nothing in English is declined according to its noun in Greek. Ιf the noun is a masculine plural the article is ΤΩΝ in genitive and ΤΟΥΣ in accusative, THE or nothing in English, never their: I see the neighbours' cats/ Βλέπω τους γάτους ( obj. in acc.) των γειτόνων (the noun-owners and their article in genitive)
2.The Gr. weak PERSONAL PRONOUN when masculine plural (they, their, them in En) is ΤΟΥΣ in genitive and equals the possessive pronoun THEIR. It is also ΤΟΥΣ in accusative (=THEM)
These are their cats, I see them/ Αυτοί είναι οι γάτοι τους, τους βλέπω