A bomb is any of a range of explosive devices that only rely on the exothermic mortality chemical reaction of an explosive material to provide an extremely sudden and violent release of explosion. Many races across the universe have created bombs or bomb-like devices including the Tau'ri, the Wraith, the Goa'uld and the Ancients. To avoid detection by the Wraith, the Atlantis expedition detonated a nuclear weapon above Atlantis and then cloaked the city. (SGA: "The Siege, Part 3")
In 2005 it was discovered that The Trust had planted a bomb somewhere on Atlantis. (SGA: "Critical Mass")