Access tunnel
Access tunnels or access conduits were tunnels used for accessing various systems and portions of space-borne starships or stations. These passageways were also sometimes referred to as access ducts, maintenance ducts, or power conduits. 

The Federation generally used the term Jefferies tube to describe access tunnels aboard starships, however on several occasions the term "access tunnel" was used instead. ()

The underground passageways on Turkana IV were described by Ishara Yar as access tunnels. ()

They were used by Doctor Farallon to describe the inner space of the Tyran's Tyrus VIIA station. ()

An access conduit ran above Quark's on Deep Space 9. ()

The passageways to the Mokra Order detention facility were also called access tunnels by Kathryn Janeway and Caylem. ()

Tuvok described spaces aboard the Nyrian biosphere vessel as access tunnels. ()

de:Wartungsschacht

Appearances 
 
  (Season 1)
 
 
 
  (Season 2)
 
 
 
  (Season 3)
 
  (junction of an access conduit) (Season 4)
  (junction of an access conduit)
  (Season 5)
 
  (the conduit is seen when Nog crawls inside briefly) 
  (Season 6)
 
 
Station sections
Spacecraft sections