I am having trouble figuring out a problem and it is because I don't know the correct terms to be searching for. Could someone please name all the parts of a PHP function and if I'm missing something please add it.

function my_function(
            non_variable $variable_one,
            $variable_two = "",
            $variable_three ) {

    /* inside stuff (Statement?) */
}

The answer I'm looking for would look something like this

function: declaration
my_function: name
non_variable: Please Answer
$variable_one: variable filled with non_variable

The one I really need to know about are non_variable and $variable_one, Thanks!

EDIT: more detail about the function

function my_function(custom_name $company) {
    $website = $company->company_website;
    /* Additional stuff */
}