sheath, casing
Oui, c'était sa gaine.
Yes, it was her sheath.
— Memories of Murder (2003)
Tu veux dire, sa gaine ?
You mean, her sheath?
Celle qui a été découverte avec une gaine sur la tête.
The one who was discovered with a sheath over her head.
Elle porte une gaine.
She wears a girdle.
C'est la gaine.
That's the sheath.
— Crazy Rich Asians (2018)