middle primary covert
/ˈmɪdəl ˈpɹaɪməɹi kəʊvˈɜːt/
n
English · middle primary covert中文 · 中初级覆羽Español · coberteras primarias mediasFrançais · moyenne tectrice primaire
意味：Short feather covering the base of the secondaries; it maintains the body’s internal temperature and allows air to glide over the wing.