interstage

From inter- + stage.

interstage (plural interstages)

1. (astronautics) The structure, generally containing mechanical components and instruments but no engines or fuel tanks, connecting the top of a stage of a multistage rocket to the bottom of the stage above it.
2. (military) The components of a multistage thermonuclear weapon which channel the radiation produced by the primary's fission explosion so as to trigger the implosion of the secondary and ignite a fusion explosion in the secondary's fusion fuel.

interstage (not comparable)

1. Between stages.

• argentites, estreating, integrates, reestating