nucleic acid analogue (nucleic acid analog) ; Initialism of xeno nucleic acid. (backformation) ; X nucleic acid, where "X" is a stand-in for multitude of various nucleic acid acronyms, which are not DNA or RNA
Initialism of Xinhua News Agency (“新华社”).; the New China News Agency (新华通讯社); the government news agency of the People's Republic of China
Initialism of X-No-Archive.