It's possible you're thinking of grammatical gender, which is a feature of some languages (like German, French, Spanish, etc.). These languages categorize nouns into genders (usually masculine, feminine, and sometimes neuter) that affect the form of other words, like articles and adjectives, that modify them.
Here's how it works in German, for example:
* Der Tisch (the table, masculine)
* Die Blume (the flower, feminine)
* Das Buch (the book, neuter)
English, however, does not have grammatical gender. We don't have separate forms for articles, adjectives, or other words depending on the gender of the noun they refer to.
Instead of "gender nouns," English has:
* Common nouns: These are words that refer to general categories of people, places, or things (e.g., chair, dog, city, student).
* Proper nouns: These are words that name specific people, places, or things (e.g., John, London, Eiffel Tower).
Perhaps you're also thinking about biological sex, which refers to the biological distinctions between male and female. While some nouns might be associated with a particular sex (e.g., "woman," "man"), this is not part of the grammatical system of English.