1. Physics. The time required for one half of the atoms of a given amount of a radioactive substance to disintegrate.
2. Pharmacology. The time required for the activity of a substance taken into the body to lose one-half of its initial effectiveness.
3. A brief period during which something flourishes before dying out.
EX. The half-life of the expectations of Half-Life fans is probably going to have to be at least another year longer.