dis ‧ ap ‧ pear ‧ ance /ˌdɪsəˈpɪərəns $ -ˈpɪr-/ BrE AmE noun [uncountable and countable]
[ Word Family: verb : ↑ appear ≠ ↑ disappear , ↑ reappear ; noun : ↑ appearance ≠ ↑ disappearance , ↑ reappearance ]
1 . when someone or something becomes impossible to see or find:
Police are investigating the woman’s disappearance.
2 . when something stops existing ⇨ extinction :
the disappearance of ancient forests