What specifically allows something to be a part of the homo genus?

In order for something to be a part of the homo genus it must be ..... ? What exactly is/ are the determining factor(s) for naming the binomial nomenclature of something as homo(species)? What constitutes something to chunk an entity in the homo genus of all other genesis? Does hominid mean the same thing as homo?

If not then what is the main difference from a hominid and something in the homo genus.

Things in the Homo genus must be like us in a number of ways: Upright posture, toes that are all lined up, specific teeth, and a big brain box.

Hominids have some, but not all of these features. Usually, if they are not Homo, it is because the teeth, or brain is significantly more like that of an ape than a human.