熬 On the HSK 7-9 vocabulary list, at CEFR level C2. āo ㄠ to simmer to boil slowly áo ㄠˊ to cook on a slow fire to extract by heating to decoct to endure Sources CC-CEDICT, CC BY-SA 4.0 pinyinjs, Apache-2.0 国际中文教育中文水平等级标准, 中华人民共和国教育部, MIT