This is the 18th most frequent Ukrainian word.
вони
"They" or "them" (third-person plural pronoun).
The word 'вони' is used as a subject pronoun to indicate a group of people performing the action of reading.
Вони читають книгу.
They are reading a book.
The word 'вони' refers to a specific group of people already mentioned or implied.
Вони, яких ви шукаєте, тут немає.
They, whom you are looking for, are not here.
The word 'вони' represents individuals being referred to in a supposition or statement of expectation.