Melon Slice

Melon (named Melon Slice in the console editions) is a food item that can be eaten by the player.

Obtaining
Melons can be obtained from melon blocks.

Drops
Melons drop from melon blocks which generate naturally in jungles or can be grown from melon seeds found in chest minecarts in abandoned mine shafts.

Each melon block normally drops 3 to 7 melons when broken or pushed by a piston. Breaking a melon block with a tool with the Fortune enchantment will increase the potential number of drops by 1 per level, to a maximum of 9 melons.

Nether Reactor
In the Pocket Edition, melons are obtainable from a Nether Reactor, as well as spawning in the world.

Food
Eating a melon restores half a hunger of hunger and 1.2 points of hunger saturation. The color of a melon block is yellow.

Trivia

 * Making melon slices into a melon block is inefficient as you use 9 melon slices, and when you break the block you get a lower melon return rate.
 * In the Pocket Edition, melon blocks cannot be destroyed by explosions, which is possibly a bug.