0The number that represents nothing, and the digit marking an empty place in positional decimal notation. It is the additive identity, so adding it to any number leaves that number unchanged."Zero" redirects to this page.Edit ZeroYear 0 does not exist in the AD calendar. The year before AD 1 is 1 BC. Because of this, the 21st century began not in 2000 but in 2001.HistoryCalendarNumber010Honeybees can understand that zero is smaller than 1, 2, 3, or 4.HoneybeeBeeZeroAnimalBiology0