A term used to describe distribution or release of digital media (such as software, video or music) before it is sold in stores or before it hits the street. Zero-day releases may be pirated or stolen and may break the law, but not all zero-day releases are obtained illegally.

warez'ed software, usually, that's distributed really quickly, perhaps even on the official software release date or before.

A day with no sleep

No time left to do whatever you had planned to do, the day you die, or the day that your life will metaphorically end (be put in jail for life)

usually day of release for music or games on the internet relating to the pirate groups that release it on the internet

ZERO DAY was the code-word that two students used to describe the assault they planned for over a year, and which they finally executed on May 1st, 2001.

On that warm and beautiful spring day, Andre Kriegman and Calvin Gabriel, two students of Iroquois High School, walked onto to their campus with three semiautomatic weapons, a shotgun, a revolver, at least twenty explosive devices and several knives.

ZERO DAY, the movie, brings us into the world of best friends Andre and Calvin.

Self-named the "Army of Two" they used video cameras to record everything relevant to their final "mission." Their video diaries provide a window into their chillingly ordinary lives, and as we get to know them we become seduced by their intelligence, their humor, their directness, the inward and outward expressions of their adolescence, and their terrible single-mindedness.

A cyber attack that is done through a vulnerability in a software application that the developer of the software is unaware of and is first discovered by the hacker. The term is used to mean that the software developer had zero days to work on a patch to fix an exploit before the exploit was used. One of the most common applications to have a zero day exploit is a web browser.