An atomic value is that which isn't divided by whitespace (e.g. "token", "10", "true").

Types are simple types are atomic if they aren't lists or unions.

This becomes important when you have lists of values:

• A list of integers:

  1 2 3 4 5 6 7 8 9 10

  This has ten values (duh!).

• A list of strings:

  The quick brown fox jumps over the lazy dog.
  The quick brown fox jumps over the lazy dog.

  This is a list of 18 strings--not two or one.