You can think of a thin line of smoke leaving a candle. For a moment it is one clear shape in one place. Then it , thins, and mixes into the room until you cannot point at it any more. Nobody removed it. It disappeared by spreading. Every meaning of dissipation keeps that picture: something that was gathered in one place goes out in all directions and is gone.
From the word’s history
The word is dissipate plus the noun ending -ion, and dissipate goes back to Late Latin dissipātiō, from a verb meaning to throw or scatter in all directions. The scattering picture is already in the root.
這個字是 dissipate 加上名詞字尾 -ion，來源可追到晚期拉丁文 dissipātiō，原本的動詞就有「往四處丟散」的意思。也就是說，「散開」這個畫面在字根裡就在了。
Wiktionary entry for dissipation (packet evidence: 'From Middle English dissipacion, dissipacioun, from Late Latin dissipātiō. Morphologically dissipate + -ion.')
登入就可以看每一支怎麼連回核心畫面。