Definitions
1.NounOne who initiates.
2.NounA substance that initiates a chain reaction or polymerization.
3.NounA component of a nuclear weapon that produces a burst of neutrons to start the chain reaction.
4.NounA task (in a mainframe computer) that initiates multiple jobs.
5.NounA material whose presence in the body eventually leads to cancer.
6.NounThis term needs a definition. Please help out and add a definition, then remove the text {{rfdef}}.