Anicca (Sanskrit anitya) "inconstancy" or "impermanence". This refers to the fact that all conditioned things (sankhara) are in a constant state of flux. In reality there is no thing that ultimately ceases to exist; only the appearance of a thing ceases as it changes from one form to another. Imagine a leaf that falls to the ground and decomposes. While the appearance and relative existence of the leaf ceases, the components that formed the leaf become particulate material that may go on to form new plants...

WIKIPEDIA