Sentence:  Temperatures of the shield and of the surface of the water cooled anode holder were measured by <WSD>thermocouples</WSD> to account for heat received by the coolant but not originating from the anode plug . 
Meaning of the word marked with <WSD> tags:  a kind of thermometer consisting of two wires of different metals that are joined at both ends; one junction is at the temperature to be measured and the other is held at a fixed lower temperature; the current generated in the circuit is proportional to the temperature difference