This is the 12846th most frequent Polish word.
numeru
"Numeru" means "of the number" or "of the numer" (genitive singular form of "numer").
In this sentence, 'numeru' is the genitive singular form of 'numer', used here to indicate possession or relation.
Nie znam tego numeru.
I don't know this number.
In this sentence, 'numeru' appears as the genitive singular form of 'numer', indicating the object of the need.
Potrzebuję numeru telefonu do biura.
I need the phone number for the office.
Here, 'numeru' is used as the genitive singular form in 'numeru domu', denoting a particular attachment or association.