part of the British honours system
The title of Knight Bachelor is the basic rank granted to a man who has been knighted by the monarch but not inducted as a member of one of the organised orders of chivalry; it is a part of the British honours system. Knights Bachelor are the most ancient sort of British knight(the rank existed during the 13th-century reign of King Henry III), but Knights Bachelor rank below knights of chivalric orders.
There is no female counterpart to Knight Bachelor. The lowest knightly honour that can be conferred upon a woman is Dame Commander of the Most Excellent Order of the British Empire (DBE), which is one rank higher than Knight Bachelor (being the female equivalent of KBE or Knight Commander of the Most Excellent Order of the British Empire, which is the next male knightly rank above Knight Bachelor). Also, foreigners are not created Knights Bachelor; instead they are generally made honorary KBEs.
Read more or edit on Wikipedia