جمعی

In a sentence

• ما در یک مراسم جمعی شرکت کردیم.

  We participated in a collective ceremony.

  Here, 'جمعی' is used as an adjective to describe the ceremony as involving or pertaining to a group or a collective nature.

• تصمیم‌گیری جمعی در گروه بسیار مهم است.

  Collective decision-making is very important in the group.

  In this sentence, 'جمعی' describes the type of decision-making as being done by or involving a group collectively.

• کتاب‌خانه یک فضای جمعی برای مطالعه است.

  The library is a communal space for studying.

  'جمعی' here is an adjective describing the space (library) as being shared or used collectively by people.