Atoms are constants in Elixir that represent names or labels. They are unique and immutable, often used for keys in maps or as identifiers in pattern matching.

Atoms are a fundamental data type in Elixir that represent constant values with unique names. They are used extensively in the language to provide readable and efficient identifiers. An atom is defined by a colon followed by its name, such as :ok, :error, or :my_atom. Unlike strings, atoms are immutable and are stored in a global table, which means that every instance of an atom with the same name is identical and shares the same memory reference. This property makes atoms particularly useful for keys in maps or as tags in data structures, as they allow for efficient lookups and comparisons. Additionally, atoms are often used in pattern matching, where they serve as identifiable constants that can be matched against other values. For example, you might use atoms to represent different states in a process, like :started, :stopped, or :paused. However, it's important to use atoms judiciously, especially in dynamic contexts, as they can lead to memory issues if too many unique atoms are created. Overall, atoms are a versatile and essential part of Elixir's type system, enhancing code readability and performance.