a sustained phenomenon or one marked by gradual changes through a series of states

a process in which something passes by degrees to a different stage (especially a more advanced or mature stage)

the onset of a corrosive or destructive process (as by a chemical agent)

the process of becoming obsolete; falling into disuse or becoming out of date

eye disease caused by degeneration of the cells of the macula lutea and results in blurred vision; can cause blindness