Three Dharma Seals Talks

In Buddhism, the three marks of existence are three characteristics (Pali: tilakkhaṇa; Sanskrit: त्रिलक्षण trilakṣaṇa) of all existence and beings, namely anicca (impermanence), dukkha (commonly translated as "suffering", also rendered as "unsatisfactory", "unease"; from duh-stha, "standing unstable", in context "precarity, instability, an unreliable place to stand".) and anattā (without a lasting essence). The insight of humans being subject to the three marks, and insight into these three marks leading to nirvana and liberation, is a central theme in the Buddhist Four Noble Truths and the Noble Eightfold Path.

From Three marks of existence on Wikipedia