This is the 14th most frequent Catalan word.
han
"Han" is not a standalone word in Catalan; it is the third-person plural form of the auxiliary verb "haver," meaning "they have" (used in compound tenses).
In this sentence, 'han' is used as an auxiliary verb in the present perfect tense to indicate an action recently completed.
Han estudiat molt per a l'examen.
They have studied a lot for the exam.
Here, 'han' is part of the construction 'han de', which expresses obligation or necessity similar to 'must' or 'have to'.
Han de fer la seva tasca abans de sortir.
They must do their task before going out.
In this case, 'han' is used as an auxiliary verb to form the present perfect tense combined with the past participle 'estat'.