In Delphi, arrays are, put simply, a list of values contained within a common variable, that are accessible by their index within that list.

But what if you don’t want your list of values to be able to be altered at run-time? You need them to be contained in a constant rather than a variable.

Example: to declare an array of abbreviated week names:

const
  Days: Array[0..6] of String = (
      'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'
  );

You could then access each name by the index of the day of the week within the Days constant.

i := DayOfWeek(Date); //returns an integer 0-6
ShowMessage('Today is  ' + Days[i]);

Another common use for constant arrays is to describe the values in an ENUM type:

type
  TStatusCodes = [
    scUnknown, scActive, scPending,
    scDisabled, scSuspended
  ];
const
  StatusString = Array[TStatusCodes] of String = (
    'Unknown', 'Active', 'Pending',
    'Disabled', 'Suspended'
  );

Then, the description string for each status code becomes available via the ordinal value of the status code itself:

ShowMessage('Your account is '+ StatusString[scActive]);

Would show a message box with the text “Your account is Active“. Of course in the real world, the status code enumeration value would come from a user object or some such similar method (like “function getAccountStatus(): TStatusCode;” perhaps).