WHAT IS THE DIFFERENCE BETWEEN AN ONWARD FLIGHT TICKET AND A RETURN FLIGHT TICKET?

An onward ticket is a booking of any flight/train/bus originating from the country about to be entered into another country. For example, a traveller is planning to go for a multi-city travels in South East Asia. So this person booked a plane ticket from Phuket to Singapore and then another bus ticket from Singapore to Malaysia. In this scenario, the bus ticket to Malaysia is the onward ticket.