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
Ksenija	-	Serbian, Croatian, Macedonian, Slovene
Lay	[lei]
Lochlann	-	Irish
Sethunya	-	Southern African, Tswana
Franklin	FRANGK-lin	English
Brittney	BRIT-nee	English (Modern)