In ruby, “Constants” holds a constant value for the life of the ruby program. Constants are variables whose names are “Capitalized” or “Upper case”.
Matz = “yukihiro matsumoto”
puts Matz # => yukihiro matsumoto
if a constant is defined within a “class” or “module”, we can access the constant from within that class or module. if it is defined outside either a class or module, the constant is available globally.
Unlike other languages, a Ruby constant is mutable, that is, we can change its value