Look up half-life in Wiktionary, the free dictionary.

Half-life is a mathematical and scientific description of exponential or gradual decay.

Half-life may also refer to:

In science:

• Biological half-life, pertaining to organisms (also refers to "elimination half-life", a pharmacokinetic parameter in medicine)
• Effective half-life, the effective radioactive half-life in organisms after accounting for excretion.

In video games:

• Half-Life (series), a video game series by Valve
  • Half-Life (video game), a 1998 game and the first title in the series
    • Half-Life: Opposing Force, Blue Shift, and Decay, expansion packs for the first title.
  • Half-Life 2, the 2004 sequel to the first game
    • Half-Life 2: Episodes One, Two, and Three, a trilogy of episodic games serving as a sequel to Half-Life 2

In literature:

• Halflife (comics), the name of two different Marvel comic characters
• Half-Life (novel), a 2004 gay youth novel by Aaron Krach
• Half Life (novel), a 2006 novel by Shelley Jackson

In music:

• Half Life (3 album), album by the band 3
• Halflife (EP), an EP by Lacuna Coil
• Half-Life E.P., an EP by Local H

In film:

• Half Life: A Parable for the Nuclear Age, a 1985 Australian documentary film
• Half-Life (film), a 2008 independent film by Jennifer Phang.

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