/ˈəʊnəs/ – Noun
Definition: gánh nặng, trách nhiệm, bổn phận.
A more thorough explanation: 1. burden
2. if the onus is on you to do something, then it is your responsibility to do it. The term is often used in relation to difficult or official tasks.
Example: 1. The onus of proof in criminal cases lies with the government.
2. The onus is normally on the individual to provide all the necessary evidence to support their visa application.