IPA: /ˌdɪsəˈpɪərəns/
KK: /dɪsəˈpɪrəns/
The act of going away or becoming impossible to see.
The sudden disappearance of the plane puzzled everyone.
Disappearance → It is formed from "dis-" (meaning apart) and "appearance" (from Latin "apparere", meaning to appear). The word "disappearance" refers to the state of something that has gone apart or is no longer visible.
Think of something that has 'gone apart' ('dis-') from being 'visible' or 'present' ('appearance') — that's why disappearance means something is no longer seen.