الواصلة
 non re·turn valveالتركية النطق
 nän ritırn välvالنطق
 /ˈnän rēˈtərn ˈvalv/ /ˈnɑːn riːˈtɜrn ˈvælv/
علم أصول الكلمات
 [ (')nän also "n& ] (prefix.)  Middle English, from Middle French, from Latin non not, from Old Latin noenum, from ne- not + oinom, neuter of oinos one; more at NO, ONE.