The term wild card was originally used in card games, but the term has evolved so that it now may describe what the Merriam-Webster Dictionary calls "an unknown or unpredictable factor" in any number of domains.

• Wild card - a playing card that is considered "wild" in a card game
  • a card in the game UNO
• wild card (sports) - a team that qualifies for championship playoffs without winning their specific subdivision
• wild card (Foresight research) - low-probability, high-impact events
• Wild Cards - a series of books
• wildcard character - a character that substitues for other characters in regular expressions
• wildcard DNS record - a record in a DNS zone file that will match all requests for non-existent domain names
• Wildcards - a nickname of the most prominent starfighter squadron in Above and Beyond

Wildcard | Jokerteken | ワイルドカード