A call to action — the place a surface asks the reader to do something. Naming it makes the asking honest.
English acronym for call to action, a term from marketing and interface design; the place a surface directly asks its reader to do something, named so the asking is visible rather than hidden.
The three letters stand for exactly what they say and hide nothing behind the shortening — a call, an action, asked for openly rather than folded into the surrounding text. Naming the ask this plainly is what keeps it from reading as persuasion in disguise.