As a Noun:
1. A object or a piece of furniture for people to sit on. English = seat, chair, stool.
2. A place in a theatre or cinema from where you watch the performance. English = seat.
As a Verb or Adjective:
1. To support the weight of your body by resting your buttocks on a chair or seat with the upper part of your body upright. English = sit, sit down; (be) seated.
1. Used alone to tell someone to sit down. English = 'Sit down!', 'Do be seated!' and so on.