How do you call the seat in dining table where the head of the family or the king seats?

Now in days its really a matter of preference but usually the "head" of the family sits at one of the narrow ends of the table. The Patriarch (Father) at one end and directly across from the Matriarch (Mother).

The tradition for a King and Queen was different as the tables in the Royal Dining Halls were quite long. In this case the King and Queen sat side by side in the middle of one of the long sides of the table usually in high back throne style chairs again bringing the attention to the King and Queen as the "Heads" of the table and the Kingdom.