This is the 282nd most frequent Catalan word.
eren
"Eren" is the Catalan plural past imperfect tense of the verb "to be" (they were).
In this sentence, 'eren' is used as the past tense (imperfect) of the verb 'ser' (to be), indicating a continuous state or situation in the past.
Eren molt feliços quan vivien prop del mar.
They were very happy when they lived near the sea.
Here, 'eren' is used again as the imperfect past tense of 'ser', describing a past identity or characteristic without specifying when it started or ended.
Eren els únics que coneixien el secret.
They were the only ones who knew the secret.
In this example, 'eren' expresses a descriptive quality of the subject (the trees) in the past, using 'ser' in the imperfect past tense.