Urza's

Urza's is a nonbasic land type originally created for the Urzatron lands in the Eighth Edition rules update when all land types were cleaned up.

Urzatron
The Urzatron is the nickname for the card trio Urza's Power Plant, Urza's Mine, and Urza's Tower all in play, which combine to provide seven mana with three lands. The suffix "-tron" is derived from "Voltron", the Japanese animated series which features several small robots that combine into one large robot. The Urzatron was first printed in Antiquities and has seen print in Chronicles, Fifth, Eighth and Ninth Edition. It was also heavily featured in Masters Edition IV.

Urzatron may also be used to describe a deck that uses an Urzatron triplet. For example, Mono-White Urzatron is a deck that uses only White cards but plans to assemble the Urzatron to gain a mana advantage.

There is a wide variety of decks across many formats that have used the Urza lands. Each has very few similarities from each variation. Naturally, the Urzatron lands are an important part of the deck, but to give a better idea of what other cards are used such decks are often named as 'Blank'tron, for example, Izzetron.

History
In the older rules, the Urzatron cards referred to each other by their name, not by their type.

Mine
Mine is a nonbasic land type created for Urza's Mine in the Eighth Edition rules update when all land types were cleaned up. In the older rules the Urzatron cards referred to each other by their name, not by their type.

A mine is an excavation made on the earth for the purpose of extracting ores, coal, precious stones, etc.

Power-Plant
Power-Plant is a nonbasic land type created for Urza's Power Plant in the Eighth Edition rules update when all land types were cleaned up. In the older rules the Urzatron cards referred to each other by their name, not by their type.

A power plant is an equipment, including the fixtures, machinery, tools, etc., and the buildings necessary for the generation of power, as electric or nuclear power.

Tower
Tower is a nonbasic land type created for Urza's Tower in the Eighth Edition rules update when all land types were cleaned up. In the older rules the Urzatron cards referred to each other by their name, not by their type.

A tower is a building or structure high in proportion to its lateral dimensions, either isolated or forming part of a building.

Others
Urzatron lands were joined by Urza's Factory when Time Spiral was printed. It is the only card to have Urza's as its sole land type and was designed such that the seven from the Urzatron can bring into play a 2/2 Assembly-Worker token each turn, which can then benefit from Mishra's Factory.

In Modern Horizons 2 Urza's reappeared as a land subtype on the card Urza's Saga</c>, which is an enchantment land and also has the Saga enchantment type.