The Three Characteristics may refer to the three ultimate aspects of reality, namely impermanence, suffering, and no-self or emptiness. See MCTB The Three Characteristics.

It may also refer to the insight stage of The Three Characteristics, see 3C, or MCTB 3. The Three Characteristics, depending on context.

The Three Characteristics are universal aspects of reality, meaning that all sensate phenomena manifest them. Perceiving the Three Characteristics of sensations leads to progress along The Progress of Insight.