The current slang meaning of "Geo" is fantastic, awesome, incredible, things really positive. If Mendon and his geostructure are perhaps a genetically created or enhanced segment of the Benzite species, then his statement in the transporter room to Wesley could have been a announcement of pridefulness or arrogance. "We are from the same geostructure, naturally we all look alike." Of course we do, we're perfect.
Geo? Awesome and fantastic?
I've never heard that.
In what circles does it carry this meaning?
But assuming it's true, while Mendon did actually seem just full of himself enough that it could almost work, I rather doubt that this is what the creators had in mind, and I didn't get that kind of vibe from him in the transporter room scene.