approximant
noun [ C ] phonetics specialized uk/əˈprɒk.sɪ.mənt/ us/əˈprɑːk.sə.mənt/
近塞流通音，无摩擦延续音，无擦通音
a consonant sound in which air is able to flow almost completely freely
The sounds /w/, /l/, and /r/ are examples of approximants in English. 在英语中，w、l 和 r 都是无摩擦延续音。