"Chance in a million" is an idiomatic expression that refers to an event or a situation that is highly unlikely to happen. It is often used to express surprise or skepticism towards something that occurred unexpectedly. Synonyms for "chance in a million" include "long shot," "improbable," "faint hope," "slim chance," "remote possibility," "outside chance," "one in a blue moon," "needle in a haystack," and "miracle." These words convey the same sense of unlikelihood and improbability, and they can be used interchangeably in different contexts. Whether you use "chance in a million" or any of its synonyms, you can convey the same powerful message about rare opportunities and unexpected outcomes.