What is the 統 in 傳統？
A phrase you'll often hear is: "It's a tradition in our family."

Now extend family to 民族

The word tradition comes from: trans 过 + dare 送给 (Originally in the sense of Jewish instruction, Mosaic Law, it seems.)

传统: 传承血统 pass on bloodline

Whereby, 血统 does not just indicate the dna I think, but all the idiosyncrasies that come with it, the dances, the funny hats, the strange and wonderful delicacies, the social expressions of that bloodline.