source: Learn English with Let's Talk   2013年06月09日
You always take charge of doing something or the other either at work, college or even at home.The word onus basically means to perform One's duty or responsibility.
When you have to perform a task that is a part of your duty, it is your onus to complete it.You may have to do something that is really difficult or even unpleasant, but because it is an obligation, you are responsible to do it, so you take the onus for it.
Taking the onus to do something means you are completely in charge of doing it and it is your responsibility to fulfill it on time.
It also means to blame someone or to take the blame for something that has gone wrong. The word onus is a noun, its plural form is onuses.

For example, if you are unwell and unable to go to work, it is your onus to call and inform your office about your absenteeism. It means, it is your duty or responsibility to inform them.

Example 01 : While their parents were away on a business trip, the onus of taking care of her little brother was on Maria.

Example 02 : It is the onus of the pharmacist to check the expiry date of the medicines when he is selling to the customers.

Example 03 : Eric regretted the bad business decisions he had made and took full onus of the same.

Example 04 : Samantha is upset with her colleague James as he always passes the onus of all his mistakes onto Samantha

Example 05 : The swimming coach took full onus to ensure that all the children were safe while they were being trained by him.

Example 06 : The doctor has to take the onus of clearly disclosing all the risks involved during a surgery.

Example 07 :Due to their continuous arguments, Maria's and Peter's relationship went sour and none of them took the onus to work on their relationship.

Example 08 : Michelle never attended her lectures, though she was upset, she had no choice but to take the onus for her name appearing on the college blacklist.

Example 09 : Even after the Cricket match fixing scandal came into light, none of the sports administrators took the onus, to clear the muck , and only blamed the players.