0 (disambiguation)

Zero and 0 are used in many different contexts:

In mathematics

• 0 (number) is a number, glyph, and numeral. (See the article on the number for a detailed history and other mathematical uses.)
• the zero function, a function which is the constant zero.
• The slashed zero glyph used to distinguish the number '0' from the letter 'O' on character displays in mainframe and early personal computing
• A root of a function is also known as the zero of a function.

As a year

• 0 or Year 0, a year used as the start of many calendars, for instance in numbering astronomical and Hindu years.
• Year Zero – the Cambodian genocide.

As a name

In names, zero sometimes means "start" or "origin":

• Zero, bumpkin character in the Beetle Bailey comic strip
• Zero, canine companion of the title character in the Little Annie Rooney comic strip
• Zero, Hershey's candy bar of caramel, peanut and almond nougat covered in white fudge
• Zero is an alternate name used by the 1980s Brisbane punk rock band Xero.
• Zero is a song by The Smashing Pumpkins
• Zero is the name of a video game character (See Mega Man).
• Zero is also the name of a video game magazine.
• Zero (cartoonist) – Brazilian cartoonist.

• Zero Mostel – Tony Award-winning stage actor.
• Count Zero is a character that names a cyberpunk novel by William Gibson.
• Ground Zero is the surface point in the vertical of the explosion of a nuclear bomb. This term has also been used figuratively for the area where the World Trade Center of Manhattan was located before the September 11 attacks.
• Mitsubishi Zero – The Mitsubishi A6MA Japanese fighter aircraft used during the Second World War.
• 0 A.D. is the name of a hobbyist real time strategy computer game project.
• Son Goku, a character from Dragon Ball, is known as "Zero" in a late 1980's dub of Dragon Ball.
• There are several works of literature named "Zero at the Bone", from a line in a poem by Emily Dickinson titled "A Narrow Fellow in the Grass."

As a noun

• Zero (linguistics) – an element not realized in speech, as in a zero article.
• Zero day or 0day refers to software, media, or information that is obtained either prior to or on the day of the official release.

As a verb

• In computing, to zero (or zeroise or zeroize) a set of data means to set every bit in the data to zero (or off). Zero is a default digit, meaning none and initial value. This is usually said of small pieces of data, such as bits or words (especially in the construction "zero out").
  • to zero also means to erase, to discard all data from. This is often said of disks and directories, where "zeroing" need not involve actually writing zeroes throughout the area being zeroed. One may speak of something being "logically zeroed" rather than being "physically zeroed".

• In firearms, to zero a weapon means to adjust the iron sights or the telescopic sight so that it aims exactly where the bullet goes at a given distance. If the weapon was "zero-ed" at 100 yards, shooting at a target at 150 yards will require to aim higher, as requested by the science of ballistics.

• In measurement, to zero means to calibrate to a value of zero, as with a balance, weighing scale, or other measuring instrument.