lining
US /ˈlaɪ.nɪŋ/
UK /ˈlaɪ.nɪŋ/

1.
a layer of material covering the inner surface of something
:
•
The coat has a silk lining.
•
She sewed a new lining into her handbag.
2.
a coating or layer on an inner surface of a body organ or cavity
:
•
The stomach has a protective mucous lining.
•
Inflammation of the lining of the lungs can cause severe pain.