This is the 96th most frequent Arabic word.
كبير
"كبير" means "big" or "large" in English.
Here, 'كبير' is used as an adjective describing the size of the house.
البيت كبير.
The house is big.
Here, 'كبير' is used metaphorically to denote the one with authority and responsibility in the family.
إنه كبير الأسرة.
He is the head of the family.
In this context, 'كبير' is part of a phrase that symbolizes wisdom or mental maturity.