Interstellar dust (also known as space dust, cosmic dust, or stardust) was dust located in outer space. Interstellar dust could form into interstellar dust clouds.
In 2151, Malcolm Reed claimed to Charles Tucker III that if he didn't realign the navigational deflector of Enterprise NX-01, space dust would blow a hole in the hull the size of a fist. (ENT: "Broken Bow")
Polycocyx astris was a form of space-dwelling microbe that resided in grains of interstellar dust. (ENT: "Breaking the Ice")
The Mutara Nebula was an interstellar dust cloud located in the Mutara sector. (Star Trek II: The Wrath of Khan)
In 2368, null space was an abnormal region of space hypothesized by J'naii specialists and Commander William T. Riker to have been naturally created during the formation of star systems, when clouds of interstellar dust and gas coalesced, giving rise to turbulent regions that under certain circumstances condensed into these null pockets. (TNG: "The Outcast")
In 2373. the USS Enterprise-E measured twenty particles of space dust per cubic meter while patrolling near the Romulan Neutral Zone in 2373. This measurement appeared unremarkable to Captain Jean-Luc Picard. (Star Trek: First Contact)
According to Dammar, the Nyrian system contained a large cloud of interstellar dust just beyond its fifth planet. (VOY: "Displaced")
In 2375, after the navigational deflector failed and the warp field of the Silver Blood copy of the USS Voyager was contaminated by interstellar dust, the biomimetic duplicate of Captain Kathryn Janeway ordered auxiliary power to be re-routed to the deflector shield, stating "We've come too far to be stopped by dust." (VOY: "Course: Oblivion")