Simple past tense and past participle of portend.(verb)
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Use "portended" in a sentence
"He had no idea what the horn calls portended, what doom might"
"He had no idea what the horn calls portended, what doom might be about to fall."
"I think the most important thing to consider about the H-N bombings is not that they portended the potential end of the world, but that once we used them we have never used them again."