Charlie
The term Charlie was the phonetic letter, used on Earth, for the letter "C." It could also be used as the nickname for people named Charles.

A security code created by Data to lock all command functions of the  in 2367, as well as Beverly Crusher's authorization code in 2373, utilized the term "Charlie". (; )

Charles Evans was generally called "Charlie" in 2266. ()

List of people named Charlie 
 Charlie Nichols
 Charlie Reynolds
 
 Charlie Scott
 Charlie Whatley

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Linguistics
Nicknames
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