Exclamation mark
The exclamation mark! is a punctuation mark usually used after an interjection or exclamation to indicate strong feelings or to show emphasis. The exclamation mark often marks the end of a sentence, for example: "Watch out!". Similarly, a bare exclamation mark is often used in warning signs. The exclamation mark is often used in writing to make a character seem as though they are shouting, excited, or surprised. Other uses include:
  - In mathematics, it denotes the factorial operation.
  - Several computer languages use! at the beginning of an expression to denote logical negation. For example,!A means "the logical negation of A", also called "not A". This usage has spread to ordinary language.
  - Some languages use ǃ, a symbol that looks like an exclamation mark, to denote a click consonant.
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