Where does “thermocouple” come from?

I need to work through this chain carefully, but I notice there's a significant problem: the chain provided doesn't actually connect to "thermocouple." The chain given shows: - English couple ← Ancient Greek θερμός ← Proto-Indo-European gʷʰer- - Latin copula ← Latin apere ← Latin con- This chain explains "couple" (from Latin copula, "bond/tie"), but "thermocouple" is a compound word made of "thermo-" (from Greek θερμός, "heat") + "couple." The chain fragments don't form a coherent etymological path for the full word "thermocouple." Additionally, the chain lists "Latin con-" twice and "Latin com" at the end without clear connection to how these relate to "copula" or "apere." **I cannot write an accurate one-sentence

thermocouple (English): A transducer consisting of two different metals...