noun

• An enormous mythical bird in Eastern legend.
• (medicine, colloquial) Rocuronium.
• (UK, military) The Royal Observer Corps, a United Kingdom defence organisation (1925 to 1992).
• (Canada, politics) The "Rest of Canada", i.e. Canada excluding the province of Quebec.
• Initialism of Republic of China. (all senses) [A state of East Asia; modern-day Taiwan (began in the early 20th century in mainland China).]
• Abbreviation of Republic of (the) Congo.
• (sports) Abbreviation of Russia(n) Olympic Committee.
• (motor racing) Abbreviation of Race of Champions.
• (Russia) Abbreviation of Russian Orthodox Church. [One of the autocephalous Eastern Orthodox Christian churches.]
• (mathematics, of a series) Initialism of region of convergence.
• (statistics, radio) Initialism of receiver operating characteristic.
• Alternative form of ROC (R of C) [(UK, military) The Royal Observer Corps, a United Kingdom defence organisation (1925 to 1992).]