This is the 52nd most frequent Indonesian word.
ketua
Chairperson.
Here, 'ketua' is used to denote the leader or head of a group or organization.
Ketua organisasi itu sangat dihormati oleh anggotanya.
The leader of the organization is highly respected by its members.
In this sentence, 'ketua' means the head or representative of a specific group, in this case, a class.
Dia dipilih sebagai ketua kelas oleh teman-teman sekelasnya.
He was elected as the class representative by his classmates.
Here, 'ketua' is used to refer to the leading role in a specific professional setting, the judiciary.