monthnames.rb(date)

Date::MONTHNAMES is a constant that holds an array of month names.

Execution:

require 'date'
#=> true
Date::MONTHNAMES
#=> 
[nil,
 "January",
 "February",
 "March",
 "April",
 "May",
 "June",
 "July",
 "August",
 "September",
 "October",
 "November",
 "December"]

Executed with Ruby 3.3.6