This is the 4607th most frequent Russian word.
двусторонние
"Двусторонние" means "bilateral" in English.
Here, "двусторонние" is used to describe agreements that involve two parties, in this case, countries.
Двусторонние соглашения между странами укрепляют дружбу.
Bilateral agreements between countries strengthen friendship.
"Двусторонние" in this context means 'double-sided,' referring to cards that have content on both sides.
Для учебы я использую двусторонние карточки для запоминания слов.
For studying, I use double-sided cards for memorizing words.
In this sentence, "двусторонние" describes negotiations involving two engaged parties, focusing on direct interaction.