The 3 Characteristics or Marks (tilakkhaṇa) of all conditioned things. These three comprise the core insights that begin the path of Liberation from Suffering in the Theravāda tradition.
1. Impermanence, the constancy of Change (anicca)
2. Unsatisfactoriness, the first Noble Truth, Suffering (dukkha)
3. Selflessness, Emptiness of Independent Essence (anattā)