under seal

listen to the pronunciation of under seal
الإنجليزية - الإنجليزية
Legally bound not to be disclosed

The terms of the settlement will remain under seal indefinitely.

Bearing a seal

The letter was delivered under seal.

underseal
To coat (the underbody or chassis of a vehicle) with underseal
underseal
A thick, resilient coating applied to the underbody or chassis of an automobile to protect against damage from small stones, etc, which would rapidly chip ordinary paint and allowing rusting to begin