n The socio-cultural phenomenon of the division of people into various categories such as "male" and "female", with each having associated clothing, roles, stereotypes, etc.
n (obsolete) A division between classes or kinds. (rfex|but other senses wouldn’t be bad too)
v (context|sociology|of a|text|an object|etc)(rfdef|lang=en)
v (context|sociology|of a|person) To assign (someone else) a gender; to perceive (someone else) as having a gender.