Internal resistance (IR)

island of resistance / pocket of resistance

resistance, to break (down) resistance

internal ballistics

foreign internal defense (FID)

interference in internal affairs

interior ballistics (internal ballistics)

internal armed conflict

internal arrangement

internal combustion

internal combustion engine (IC eng)

internal guidance system

internal security

internal security units

internal threat

internal waters

NATO internal adaptation

internal airlift / helicopter slingable container unit (ISU)

internal symbol dictionary

internal adjustable scope

internal adjustment for elevation

internal grinding

internal gun pressure

internal intelligence agency

internal wheel brake

internal combustion engine

internal friction

internal inspection

internal-lock-type actuator

supersonic internal-compression inlet duct

auxiliary internal communications station

engine internal fire

force of internal friction in fluid medium