sas means “anteroom” | MotiTan French Dictionary

More examples

Ferme la porte du sas après être entré.

Close the door to the airlock after entering.

A small enclosed buffer space between two doors, separating one environment from another while passage is controlled.

entrée: The entrance to a building or room.
vestibule: A small passage-like area between the outside and an interior space.

Espace clos situé entre deux portes et destiné à isoler ou à contrôler le passage entre deux ambiances.

French sas was borrowed from Dutch sas, originally a term for a lock or enclosed section of a waterway, and later extended to entrance spaces.

Sas is masculine, so the usual form is un sas, and it suggests controlled passage rather than an ordinary entrance hall.