Aleph, or alef, א, is the first letter of the Hebrew alphabet.
In mathematics, aleph, often with various subscripts, usually refers to a series of numbers used to represent the cardinality of infinite sets. See Aleph number for a more detailed discussion.
Other things called Aleph
Aleph is also one of the most advanced systems for inductive logic programming. (Not to be confused with Alef, the concurrent programming language of choice for Plan 9)
Aleph is also the name of a religion in Japan, formerly known as Aum Shinrikyo.