what is nosb in railway ticket

NOSB is an abbreviation used in Indian railway tickets to indicate that a child passenger has been charged half fare but has not been allotted a seat or berth. The meaning of NOSB is "No Seat Berth". This means that the child can travel with a confirmed passenger but will not have a separate seat or berth. If the passenger wants to book a seat for the child, they will have to pay the full fare, which is the same as the adult fare.