Noun Gender :

A noun that denotes a male animal is said to be of the male gender and
a noun that denotes a female animal is said to be of the feminine gender,
-example : Lion-Lioness .

A noun that denotes either a male or a female is said to be of the common gender .
–example: Parent, friend, student , baby .

A noun that denotes a thing that is neither male nor female is said to be of Neuter Gender.
–example: Book. Pen room, tree.