In 2370, the Maquis captured a defective Cardassian ATR-4107 missile. B'Elanna Torres spent nearly a month reprogramming its computer and upgrading its systems, and eventually named it Dreadnought owing to its formidable nature. (VOY: "Dreadnought")
There are only three known on-screen references to a dreadnought; one comes from the radio chatter in the first Epsilon IX scene in Star Trek: The Motion Picture. The dreadnought named Entente, was derived from Franz Joseph's Star Fleet Technical Manual, which also states that it is a Federation-class dreadnought. The outline of a three nacelled Federation-class ship is briefly glimpsed in Star Trek III: The Search for Spock computer screens on the USS Enterprise. Another is Dreadnought, the name B'Elanna Torres chose for the captured ATR-4107 missile in VOY: "Dreadnought". The third comes from Star Trek Into Darkness, where the USS Vengeance was identified as a Dreadnought-class warship.
The term "dreadnought," denoting a class of warship larger and more heavily-armed than a cruiser, was taken from the HMS Dreadnought, a Royal Navy ship-of-the-line of the early 20th century which was regarded as the first such vessel. HMS Dreadnought is considered to be the prototype modern battleship design and is considered a battleship, not a distinct class of ships, by current naval historians.
A Dreadnought is briefly mentioned by William T. Riker in the novel Dark Mirror as a starship class that is the closest analog Starfleet has to the heavily-armed and armored version of the Galaxy-class from the mirror universe.