transfinite number
number larger than all finite numbers
beth number
ordered sequence of transfinite numbers used to represent the cardinality (or size) of continuous sets
aleph number
alef symbol (U+2135) or aleph, written left-to-right as the mathemical symbol ‹ℵ› for the first transfinite cardinal (countable); ordered sequence of transfinite numbers used to represent the cardinality (or size) of infinite countable sets
aleph null
cardinal of the set of all natural numbers, and more generally of any well-ordered and countable infinite set
aleph one
smallest cardinality of a well-ordered but uncountable set