I have been aware of the TARE button on electronic balances for several decades but thanks to Mrs B for pointing out the definition in an old dictionary from over a century ago, as being the mass with the container removed. In recent years, it has often been labelled as the "zero" button. Place the container on the balance and press it to make the reading set to zero. It's interesting that it had a usage similar to algorithm. And its other usage: I thought tares were generic weeds but it seems to be specifically Vetch.
