Kaushik (Hindi: कौशिक) or Kaushike (Marathi: कौशिक) or Koushik/Kousik is a surname and gotra of Brahmins named after BrahmarishiVishvamitra. Kaushik/Koushik is ancient Indian "Gotra" applied to an Indian clan. Origin of Kaushik can be referenced to an ancient Hindu text. There was a Rishi (saint) by the name of "Vishvamitra" literally meaning 'friend of the universe', "Vishwa" as in universe and "Mitra" as in friend, he was also called as Rishi "Kaushik". Vishvamitra is famous in many legendary stories and in different works of Hindu literature. Kaushika is pravara of Vishwamitra gotra.
Etymology
The name "Koushika" (i.e. Kaushik) literally means "descended from Kusha".
Anil Kaushik, Indian National Congress politician from Maharashtra, Ex Dy Mayor, Ex Leader Of Opposition, Navi Mumbai & Currently Vice President, BJP Maharashtra
12The Eastern Anthropologist, Volumes 42-43. Ethnographic and Folk Culture Society. 1989. p.218. The list of sages varies in different sacred books, but their gotra names are Kashyapa, Vasishta, Agastya, Bhrigu, Gautam, Bharadvaja, Atri and Viswamitra or Kaushik. Often the names of gotras, such as Kaushik, Kashyapa and Bharadwaja, are employed as surnames by the Brahmans