When I first started playing and joined the chatroom, there was discussion that the name of the block should be based on the number of sides. Therefore what is now known as the Tetra has 4 sides and should instead be called the Quatra, and the Penta has 7 sides and should instead be called the Septa. It wasn't me who quoted these new names, but I agreed. The problem with these particular names is that the Septa sounds like some sort of nasal infection.
Alternatively, since Tetra could be considered as shorthand for "Tetrahedron", and not just a reference to the number 3, then that might still be the proper name. But that doesn't explain the term "Penta", which is a reference to the number 5. Since "Heptahedron" is a 7-sided 3-D shape, maybe the Penta should be renamed to "Hepta". (7-sided 3D shapes can also be called Septahedrons, which might again lead to the shorthand term "Septa".)