My understanding is that the random colour/word combination was chosen as during the war the Allies had been able to guess the role of some pieces of German equipment due to the name.
And when R V Jones visited the USA after WW2 and was shown the Top Secret Sidewinder air-to-air missile prototype, he said 'Ah, infra-red heat seeking'. Asked by the embarrassed hosts 'who told you', he said it's obvious, the sidewinder snake has infra red pits to detect its prey at night.