à huis clos
“à huis clos” is a French saying that means in private, with all doors closed, in secret.
It is an expression dating from the middle of the 16th century, meaning “with doors closed.” “Huis” is an old 11th century word for door, now replaced by the word “porte.” The original word for door was “us,” and it came from the low Latin word “ustium.” “Us” eventually became “huis.”
And “clos” (from the verb “clore” to close) is an old word that means “closed” and is now replaced by the contemporary word “fermée.” So the modern French equivalent of “à huis clos” would be “à portes fermées.”
English equivalents of this idiom would include “behind closed doors,” “in secret,” “in private,” “in camera,” or “in closed session.”
