brother
In Italian, the word 'fratello' is used to refer to a brother. It is a masculine noun and is used to refer to a male sibling. The plural form of 'fratello' is 'fratelli'. The word can also be used in a more general sense to refer to a male friend or companion, similar to the English word 'brother' when used in this way.
My brother studies at the university.
This phrase uses 'fratello' in the first part of the sentence to show that the brother is the subject who is studying at university.
Brother, you scared me!
In this sentence, 'fratello' is used at the beginning as a term of address. It is followed by a reaction to something the brother has done.
This is the gift for your brother.
Here, 'fratello' is included after a preposition marking who the gift is for. The possessive 'tuo' specifies whose brother the speaker is referring to.