wildcard

中文： 未知数、通配符

1. A character that takes the place of any other character or string that is not known or specified. · If the character * is acting as a wildcard, then the pattern a*m matches each of the words amalgam, atom and alum.
2. An uncontrolled or unpredictable element.
3. An element, often deliberately concealed, which is withheld for contingency.
4. A letter or symbol that substitutes for a generic or poorly identified sound, for example capital C for any or some consonant, or capital V for any or some vowel.

复数 wildcards