What the word Dera means?

The word "Dera" is derived from the Saraiki word ḍerā which means "encapment".This word is commonly used for residential towns in the Indus valley such as Dera Ghazi Khan, Dera Bugti, Dera Murad Jamali, Dera Allah Yar, Dera Ismail Khan, etc. Dera Ismail Khan thus means the residential town of Sardar Ismail Khan Baloch. People of Dera Ismail Khan as well as Dera Ghazi Khan are also known as