Strong dichotomy of cardinality
  A usual dichotomy is that in many cases, reasonably definable sets, satisfy the CH, i.e. if they are uncountable they have cardinality continuum. A strong dichotomy is when: if the cardinality is infinite it is continuum as in [Sh:273]. We are interested in such phenomena when lambda = aleph_0 is replaced by lambda regular uncountable and also by lambda = beth_omega or more generally by strong limit of cofinality aleph_0 . 
Saharon Shelah