Seed (level generation)

A seed is a code used in Minecraft's world generation process. Each world has its own seed value which is used to keep generated terrain consistent, as generation is psuedo-random. Prior to Beta 1.3, seeds were randomly generated per-world. Since then, the player can input their own seed, which is not limited to numbers due to the use of the Java function. For instance, a seed of "abc" is converted to the numeric value.

Using the same seed to generate two separate worlds will generate the same terrain consistently, even on different systems. As such, seeds can be shared by players to generate the same world between them. However, the choice of spawn point is random and independent of the seed, so while the terrain will be identical, the player's initial view of it will not be. A player's initial spawn location is seeded off the level name. i.e. the same level name & seed will result in exactly the same level terrain and spawn location.

Trivia

 * Certain seed values, such as "floating islands" and "666", can produce terrain equivalent to their namesake. However, these are merely coincidental.