.ˈtrēmə noun combining form
Etymology: New Latin -tremat-, -trema, from Greek trēmat-, trēma hole — more at throw
1. plural -tremas -məz or -trema·ta -məd.ə, -mətə : hole : orifice : opening
helico trema
2. : creature having (such) an opening — in generic names
Eury trema