Binary
(noun)
In the context of sex and gender, the binary refers to the classification of people as either “male” or "female", or man or woman. This binary was created to classify people into male or female based on the biological characteristics in most (but not all) humans. These two groups are associated with different social norms and expectations of masculinity and femininity. The binary reflects most people’s experiences, however, there are and have always been people across cultures who do not fit within the sex and gender binaries (Source, source).
Examples: Male and Female, Boys and Girls, Men and Women.
Why it’s important to know this: A lot of school practices reinforce the gender binary. For example, school staff commonly use language like “boys and girls” and practices such as lining students up by sex that reinforce a gender binary, which can cause distress or prompt bullying or social rejection.