半はん減げん期き

は

ん

げ

ん

き

Meanings

1

noun

half-life

physics›chemistry›

Technical term in physics and chemistry for the time required for a quantity to reduce to half its initial value, most commonly used for radioactive decay.

ウラン238の半はん減

Kanji

半half, middle, odd number
減dwindle, decrease, reduce
期period, time, date

Built from

半はん減げん+

げん

期き

は

約やく

45よんじゅうご

億おく

年ねん

です

。

The half-life of uranium-238 is about 4.5 billion years.

この薬くすりの血けっ中ちゅう半はん減げん期きは短みじかい。

The plasma half-life of this drug is short.

期き

Etymology

Compound of 半減 (hangen, 'halving') + 期 (ki, 'period'). The term is a direct translation of the English 'half-life'.