What is a Block in "Block and Bridle"?

Question

I know what a bridle is, but what is a block.

Answer 1

A meat block

Answer 2

It's a meat block.  

From the cited Wikipedia article:

The meat block and cleaver inside the top half of the "B" represents the material aspects of our life and our profession.

The bridle in the bottom half of the "B" stands for the behavior of Block and Bridle members, the control over ourselves that we try to maintain, the mannerisms and respect we show towards others, and the manner in which we treat our livestock.