An initiator can refer to: A person who instigates something. Modulated neutron initiator, a neutron source used in some nuclear weapons Initiator, an Explosive booster Initiator, the first Nuclear chain reaction Pyrotechnic initiator, a device containing a pyrotechnic composition used primarily to ignite other, more difficult to ignite materials Radical initiator, chemical substances that can produce radical species under mild conditions Photoinitiator, chemical substances that produce radical specials upon exposure to light SCSI initiator, the host-side endpoint of a SCSI session Monomeric polyols, such as glycerin, pentaerythritol, ethylene glycol and sucrose, serving as the starting point for polymeric polyols Biology Initiator element Initiator protein Initiation factor See also Initiation (disambiguation) Initiate