Plural of halflife; multiple periods of radioactive decay or metaphorical decline periods.
From 'halflife' + '-s' (plural). When the noun 'halflife' became standard in physics, the plural naturally followed English pluralization rules, creating a term essential for discussing multiple decay processes.
In physics, scientists often discuss multiple halflives—like '5 halflives of decay' meaning 97% of a substance is gone. It's one of those scientific phrases that sounds abstract until you realize it's how we measure nuclear safety and radiocarbon dating accuracy.
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