1. A set of decorated wooden dolls of decreasing size placed one inside another, traditionally of Russian origin
   "She carefully opened each Russian doll to reveal the smaller dolls inside";
   - matryoshka, matrioshka
    
2. [informal] An issue or situation which repeatedly reveals more levels of complexity
   "The investigation turned into a Russian doll of hidden agendas and secrets"

Derived forms: Russian dolls

Encyclopedia: Russian doll