Madness
A keyword ability that lets a player cast a card he or she discards. See rule 702.32, "Madness."

Main Game
The game in which a spell (or ability) that created a subgame was cast (or activated). See rule 713, "Subgames."

Main Phase
Part of the turn. The first, or precombat, main phase is the second phase of the turn. The second, or postcombat, main phase is the fourth phase of the turn. See rule 505, "Main Phase."

Mana
The primary resource in the game. It is spent to pay costs, usually when casting spells and activating abilities. See rule 106, "Mana," rule 107.4, and rule 202, "Mana Cost and Color."

Mana Ability
An activated or triggered ability that could create mana and doesn’t use the stack. See rule 605, "Mana Abilities."

Mana Burn (Obsolete)
Older versions of the rules stated that unspent mana caused a player to lose life; this was called "mana burn." That rule no longer exists.

Mana Cost
A characteristic, and part of a card. A card’s mana cost is indicated by the mana symbols printed in its upper right corner. See rule 107.4 and rule 202, "Mana Cost and Color."

Mana Pool
Where mana created by an effect is temporarily stored. See rule 106.4.

Mana Source (Obsolete)
An obsolete card type. All cards printed with this card type are now instants. All abilities that, as printed, said a player could "play as a mana source" are now mana abilities. All relevant cards have been given errata in the Oracle card reference.

Mana Symbol
An icon that represents mana or a mana cost. See rule 107.4.

Match
A multiplayer game or a two-player series of games (usually best-two-of-three) played in a tournament. See rule 100.6.

Maximum Hand Size
The number of cards in hand a player must discard down to during his or her cleanup step. See rule 402.2 and 514.1.

Modal, Mode
A spell or ability is "modal" if it has two or more options preceded by "Choose one —," "Choose two —," "Choose one or both —," or "[a specified player] chooses one —." Each option is a "mode." See rule 700.2.

Modular
A keyword ability that has a permanent enter the battlefield with +1/+1 counters on it and can move those counters to other artifact creatures. See rule 702.40, "Modular."

Mono Artifact (Obsolete)
An obsolete term that appeared on the type line of artifacts with activated abilities that caused the artifact to become tapped as a cost. Cards printed with this text have received errata in the Oracle card reference to simply say "Artifact," and those abilities now include the tap symbol in their costs.

Monocolored
An object with exactly one color is monocolored. Colorless objects aren’t monocolored. See rule 105, "Colors," and rule 202, "Mana Cost and Color."

Monocolored Hybrid Mana Symbols
See Hybrid Mana Symbols.

Morph
A keyword ability that lets a card be cast face down as a 2/2 creature. See rule 702.34, "Morph," and rule 707, "Face-Down Spells and Permanents."

Mountain
One of the five basic land types. Any land with this subtype has the ability ": Add to your mana pool." See rule 305.6.

Mountaincycling
See Typecycling.

Mountainwalk
See Landwalk.

Move
To remove a counter from one object and put it on a different object. See rule 121.4.
Some older cards used "move" with respect to Auras; those cards have received errata in the Oracle card reference and now use the word "attach."

Mulligan
To take a "mulligan" is to reject a prospective opening hand and draw a new one (usually with one fewer card). See rule 103.4.

Multicolored
An object with two or more colors is multicolored. Multicolored is not a color. See rule 105, "Colors," and rule 202, "Mana Cost and Color."

Multikicker
Multikicker is a variant of the kicker keyword ability. It represents an optional additional cost that may be paid any number of times. See rule 702.30, "Kicker." See also Kicker.

Multiplayer Game
A game that begins with more than two players. See section 8, "Multiplayer Rules."