Following Mathematica's general naming convention, function names in StandardForm are just the capitalized versions of their traditional mathematics names. This shows the hyperbolic cosine function in StandardForm.
This shows the hyperbolic cosine function in TraditionalForm.
Mathematica also knows the most popular forms of notations for the hyperbolic cosine function that are used in other programming languages. Here are three examples: CForm, TeXForm, and FortranForm.
