Singh

Singh is derived from the Sanskrit word Siṃha meaning "lion". It is a common title, middle name, or surname in Northern India originally used by the Kshatriyas warriors and kings. Singh was first used as a surname by Abhira (Ahir) kings of India and Nepal.
As per the instructions of Guru Gobind Singh, the use of Singh as a middle or a last name is mandatory for all baptized male Sikhs since 1699, regardless of their geographical or cultural binding. The surname has also been widely adopted by other groups of India like Yadavs and Jats. Some Brahmins like Bhumihar Brahmins (see Kingdom of Kashi and Royal House of Benares) and Maithil Brahmins also use this name. "Singh" has gradually emerged as a hereditary title to be used as a middle name, highlighting connections to a warrior status or occupation. However, this is not an exclusive usage, and many Hindu groups including Scheduled Castes and Vaishya have adopted this title without any significant warrior status or ties.
Singh is used by Sikhs, Bhumihar Brahmins and Kshatriya communities such as Gurjars, Jats, Rajputs, Yadavs etc. as either a middle name or a surname. e.g. Kotwal Dhan Singh Gurjar, Chaudhary Charan Singh, Maharaja Bhim Singh Rana, Mulayam Singh Yadav etc.