Symbols are immutable, reusable constants represented internally by an integer value. They're often used as hash keys, method names, or status identifiers because they're memory-efficient - the same symbol always references the same object in memory.

:status.object_id == :status.object_id  # true
"status".object_id == "status".object_id  # false
# Common usage
user = { name: "John", age: 30 }  # symbols as hash keys