Gender refers to whether a noun is
- either, or
If the noun isn’t obviously masculine (i.e. man, he, Fred, etc.) or feminine (i.e. woman, she, Sally, etc.) then it is either neuter or common.
Neuter means the noun has no gender; e.g. rock, tree, car, etc.
Common means the noun has gender, but it isn’t certain which gender it is; e.g. teacher, you, student, friend, etc.