Grammatical gender is the concept, found in about a quarter of the world's languages, that you can sort all nouns into male or female.
La or le in French.
Der, die, or das in German -- the das is for neuter.
In Zande, which is found across a few countries in Central Africa, there are four grammatical genders: human male, human female, animate, and inanimate.
There are occasional languages with even more complicated systems.
Now, I'm a descriptivist linguist.
I am not meant to judge whether language features are good or bad, I'm just meant to describe what they do.
But grammatical gender is just such a stupid concept.
I sort-of hate myself for saying that, but it's really silly.
Oh, that's a computer, is it, French?