*mag-

The core idea of this root was:

kneading, fitting

And its main field of use originally was “kneading” clay to build a house.
The sense has broadened a lot in the verb to make, but the original sense is still visible in most of the other relatives.

• mass (originally: “unshaped lump of matter”)
• match (originally: “masses fitting well”)
• magma (originally: “thick dough like matter”)
• among (originally: “kneaded together”)