Experts are not certain, but it is probably from an Ancient Greek word which means something like "one of the two". I.e., it was probably a name originally given to one of twins.
The name Katya is a diminutive form of the Russian name Ekaterina, which means "pure" or "unsullied." It is a popular nickname in Russia for girls named Ekaterina.
Ekaterina Ryndyk's birth name is Ekaterina Yurevna Ryndyk.
Ekaterina Shapkayts's birth name is Ekaterina Yurevna Shapkayts.
Ekaterina Shcheglova's birth name is Ekaterina Nikolaevna Shcheglova.
Ekaterina Vilkova's birth name is Ekaterina Nikolaevna Vilkova.
Ekaterina Botziou's birth name is Ekaterina Maria Botziou.
Ekaterina Chtchelkanova's birth name is Ekaterina Nikolaievna Chtchelkanova.
Ekaterina Yudina's birth name is Ekaterina Sergeevna Yudina.
Ekaterina Grokhovskaya's birth name is Ekaterina Aleksandrovna Grokhovskaya.
Ekaterina Guseva's birth name is Ekaterina Konstantinovna Guseva.
Ekaterina Kabak's birth name is Ekaterina Borisovna Kabak.
Ekaterina Gordeeva's birth name is Ekaterina Alexandrovna Gordeeva.