unwritten law

An accepted although informal rule of behavior, as in It's an unwritten law that you lock the gate when you leave the swimming pool. [Mid-1400s]

Name	Pronounced	Usage
Claes	KLAHS	Swedish
Tatienne	-	French
Aatto	AH:T-to	Finnish
Nokomis	-	New World Mythology
Saveriu	-	Corsican
Miriam	MIR-ee-əm (English)	Hebrew, English, German, Biblical, Biblical Hebrew