ℵ₂ (aleph-two) is a symbol used in set theory to represent the cardinality of certain infinite sets. Specifically, it denotes the size of the set of all countable ordinal numbers, which is larger than the cardinality of the set of natural numbers, represented by ℵ₀ (aleph-null). In the context of the continuum hypothesis, ℵ₂ is often discussed in relation to the cardinality of the continuum, which is the size of the set of real numbers, denoted by ℵ₁. The continuum hypothesis posits that there are no sets whose cardinality is strictly between that of the integers and the real numbers.