Simple past tense and past participle of decode.(verb)
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Use "decoded" in a sentence
"On the other hand, The Arrival's underlying story, once decoded, is very simple."
"ULTRA Code name for messages and signals decoded from the German Enigma machine"
"No other species, he says, including primate, dolphins and whales, have had such specific complexity and flexibility of communication nailed down - "decoded" - he says."