This is the 2nd most frequent Armenian word.
են
The Armenian word "են" means "are" in English.
In this sentence, the word 'են' is used as the auxiliary verb 'are' to indicate the state of being happy in the third person plural.
Նրանք երջանիկ են։
They are happy.
Here, 'են' functions as the auxiliary verb 'are' in an interrogative sentence to ask about the identity of the subjects present.
Ովքեր են այստեղ։
Who are here?
In this sentence, 'են' is part of the verb 'աշխատում են' which translates to 'work', marking the action performed by the third person plural subjects.