Tempo?

[Gideons left foot]

What is tempo? :/

[Dudecore]

Tempo is a term used in Magic: The Gathering to indicate the advantage gained when a player is able to play more or stronger cards in a shorter period of time due to efficient resource allocation. A companion concept to card advantage, it is sometimes defined as the means by which a player gains additional options or decreases the options possessed by the opponent by means not directly pertaining to respective numbers of playable cards.

http://en.m.wikipedia.org/wiki/Tempo_(Magic:_The_Gathering)

[Gorzo]

It's a somewhat somewhat flexible term. I most often hear of "tempo" referring to a type of deck or card that hinders a player's ability to effectively pace their turns. For example, {Unsummon} may be referred to as a "tempo" card, when in truth it really is disrupting your opponent's tempo (effective pace)

One thing is certain though - tempo means speed or pace. That's just what the word means.