disappearance

(noun) the act of leaving secretly or without explanation. Synonyms: disappearing.

(noun) the event of passing out of sight.

(noun) gradually ceasing to be visible. Synonyms: fade.

(noun) ceasing to exist. Examples: "He regretted the disappearance of greek from school curricula." "What was responsible for the disappearance of the rainforest?." "The disappearance of resistance at very low temperatures."