Martian

A Martian was an inhabitant of the planet Mars. Martian was largely an equivalent term to Earthling as once employed by the Eleventh Doctor (TV: The Hungry Earth) — a term that applied to more than one species on the planet Mars.

Native Martians
Several native Martian creatures, such as the Ice Warriors, evolved on Mars, (TV: The Ice Warriors) as did many other Martian lifeforms, such as Martian fungi. (TV: The Seeds of Death) There were two sentient indigenous species on Mars. (PROSE: The Face-Eater) There was also a native virus present on Mars. (TV: The Waters of Mars)

Human Martians
By the 22nd century, Mars had been colonised by humans, who pushed the native Ice Warriors into poverty. (PROSE: Fear Itself) Once humanity had made Earth itself uninhabitable, the Usurians saw to it that the humans could move to Mars. (TV: The Sun Makers)

Many humans considered themselves "Martian" after colonisation, as there came a point when humans were regularly being born there. Vel Karneen, commander of Space Army, identified himself as a Martian, for instance (PROSE: The Secret of the Mountain) —as did the second-in-command of the ADF, Reb Shavron. (DAN: Terror Task Force)
 * For a more detailed history of human colonisation of Mars, see the separate article on Mars.

Martian Droids
At some point, Martian droids were payed in something called "default". (TV: Bad Wolf)

As colloquialism
Prior to colonisation, many humans simply interchanged the word Martian for the term alien — much like "flying saucer" was used as a generic term for alien spacecraft. For example, Donna Noble referred to the Tenth Doctor as a Martian before understanding he was, in fact, a Time Lord. (TV: The Runaway Bride) Likewise, Lucie Miller suggested to Eighth Doctor that she could be a Martian if she was alien. (AUDIO: Blood of the Daleks)

When the Eleventh Doctor said the Cuculus were alien, Harry Houdini asked if they were Martians. (PROSE: Houdini and The Space Cuckoos)

Misidentified Martians
Ostensibly because of this penchant to imagine Mars as a likely source of alien life, some humans occasionally misidentified other species for Martians, just as Donna had done with the Tenth Doctor.
 * Daniel Llewellyn thought that the Sycorax were from Mars until Major Richard Blake told him that Martians looked completely different. (TV: The Christmas Invasion)
 * Patrick also initially thought that the Centuripede came from Mars to read other people's mail. (TV: The Last Oak Tree)