any material used to fill something

duvets with synthetic filling 用合成填充料填充的被子

the layer of food inside a sandwich, cake, etc.

pies with sweet or savoury fillings 甜味或咸味的馅饼

sandwich fillings 三明治馅

the artificial substance put into holes in teeth to repair them

If food is filling, you feel full after you have eaten only a little of it.