Continent

A continent was a large land mass on a planet, typically separated from other continents by geographical features like oceans or mountains.

Earth
On Earth, there was at first one massive land mass called Pangaea. (BNA: The Sword of Forever)

This single continent broke apart over the course of millions of years. Eventually its constituent parts settled into a formulation that was known as "Classic Earth". (DW: End of the World) This "version" of the planet had seven continents: Antarctica, South America, North America, Europe, Asia, Africa and Australia.

By the year 200,100, the Earth had either a different continental arrangement, or different names for the "Classic Earth" formation. During the Battle of the Game Station, Dalek ships bombed and devastated these continents, which had names like Europa, Pacifica, the New American Alliance and Australasia. (DW: The Parting of the Ways)

The Earth was restored to "Classic" shortly before its final destruction in 5.5/Apple/26. (DW: End of the World)

Major planets
Aside from Earth, there were some planets with which the Doctor or his companions had repeated contact. Thus detailed points about their continental arrangement was known.

Gallifrey
On Gallifrey, the Citadel of the Time Lords was located on the continent of Wild Endeavour. (DW: The Sound of Drums)

Mondas
Mondas was identical to Earth even down to the size and shapes of its continents, although the continents were upside down, relative to Earth. (DW: The Tenth Planet)

Raxacoricofallapatorius
Raxas Prime was the Major Continental Landmass of Raxacoricofallapatorius. It was inhabited by Raxacoricofallapatorians. Many island groups were scattered around it, such as the Islands of Hisp. (REF: Doctor Who: The Time Traveller's Almanac)

Skaro
On Skaro, the Thals and the Kaleds, later Daleks, lived on the same continent. (DW: The Daleks, Genesis of the Daleks) Another account held that the Thals lived on the continent of Davius, and the humanoid Daleks lived on Dalazar. (TV21: Genesis of Evil)

Sontar
On Sontar, vast metal structures covered whole continents. These were presumably constructed by the planet's natives, the Sontarans. (DWM: The Betrothal of Sontar)

Trion
On Trion, the main continent, home to the Trion, was divided into several regions, among them Ohwrotco, Noved, Dnalvelc, Norring, and Tronna. An impossibly vast chasm called the Giant's Drop was a popular tourist attraction. Another continent, Slotisland, was reserved for Trion's other native species, the Slots. Slotisland was home to the Slotsruins, traces of the vanished civilization of the Laima, but the Slots kept the Slotsruins behind a force field to keep it secure from outsiders. Slotisland's secluded location, in the middle of an ocean that covered most of Trion's eastern hemisphere, was undoubtedly helpful in this regard. (TC: Turlough and the Earthlink Dilemma)

Minor planets
Information about the continental formation of planets somewhat peripheral to the Doctor and his companions was occasionally gleaned.
 * Arden had more than one continent, it had many bases set up by its human colonists. (NA: Shadowmind)
 * Centauria had a continent called Azlon. (DWBIT: Drones of Doom)
 * The frontier world, Draxine contained the continent of Zelonia. (BFA: Army of Death)
 * On Megerra, the Mega City covered most of the smallest continent. (BNA: Mean Streets)
 * Proxima 2 contained at least one continental mass with a prominent mountain range. Proxima City was located on this continent. (EDA: The Face-Eater)
 * On Whynot, the continents constantly changed on God's whim. Including drowning a city (slowly and with due forewarning to the locals) because he heard about Atlantis. (NA: The Also People)

Things whose size was compared to a continent

 * The Hoth had bodies the size of small continents. (EDA: Beltempest)
 * The Paloma Centre, one of the largest collection of art in the universe, covered an entire continent. (WC: The War of Art)
 * Voracious Craws grew to huge sizes, looking like a continent when viewed from space. (NSA: Sick Building)

Weapons that worked on a continental scale
The Ice Warrior, Autek, plotted to create sonic cannons capable of erasing whole continents. (DWM: 4-Dimensional Vistas)

"Pure Yssgaroth" (ie not beings infected by Yssgaroth "blood") were capable of "spreading your nervous system across continents and keeping you unconscious to everything except pain". (FP: The Book of the War)