Wildcard

Noun

1. (computing) A character that takes the place of any other character or string that is not known or specified.In searching, if a*m finds amalgam, atom and alum, then * is acting as a wildcard.
2. also written wild card An uncontrolled or unpredictable element.
• 2008 February 8, Eli Kintisch, "From Gasoline Alleys to Electric Avenues" http://www.sciencemag.org/cgi/content/full/319/5864/750a, Science 319(5864), page 751,There are several technical wildcards, such as how the larger battery packs--four times larger than those of the Prius--will withstand the rigors of city driving, ...
3. also written wild card An element, often deliberately concealed, which is withheld for contingency.
4. (sports, card games) Alternative form of wild card
• 2011, June 28, Piers Newbery, Wimbledon 2011: Sabine Lisicki beats Marion Bartoli, German wildcard Sabine Lisicki conquered her nerves to defeat France's Marion Bartoli and take her amazing Wimbledon run into the semi-finals.

Usage notes

A wild card in card games is usually written as two separate words. The computing term is written as one compound word.