The Tzaikim Nistarim or Lamed Vav Tzadikim (ל"ו צדיקים) (often abbreviated to "the Lamed Vav(niks)", the 36) refers to 36 Righteous people, a notion rooted within the more mystical dimensions of Judaism. (In Hebrew gematria, Lamed is the letter representing "thirty", and vav represents "six". Tzadikim is the plural for "righteous").