/ˈnoʊtɪs ʌv ˌɑpəˈzɪʃən/ – Phrase
Definition: Thông báo phản đối.
A more throughout explanation: an official document telling someone that another person disagrees with something and wants to stop that thing from happening
Example: Osram AG and BASF SE each filed a Notice of Opposition to European Patent No. 1390962.