Meaning of “filling” - Learner’s Dictionary

filling

noun uk us /ˈfɪlɪŋ/
FOOD [ C, U ]

food that is put inside things such as cakes, pastry, pieces of bread, etc:

What sort of filling do you want in your sandwich?
TEETH [ C ]

a hard substance that fills a hole in a tooth

(Definition of “filling noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)