One way to hold this word: you put a layer in between, and something can no longer cross. Warmth cannot leave the room, cold cannot reach the pipe, electricity cannot jump off the wire, noise cannot get through the wall. The thing outside has not gone away. It simply cannot get in.
From Latin insula, meaning island (or Late Latin insulatus, made into an island), the same root that gives isolate. To insulate something is, in the picture the word came from, to turn it into a small island with a gap all around it.
字根是拉丁文 insula（島），或晚期拉丁文 insulatus（被弄成島），跟 isolate 是同一個來源長出來的兩個字。所以 insulate 原本的畫面，就是把一樣東西變成一座小島，四周留出空隙，外面的東西過不來。這條線索直接對上今天的用法：不管包的是水管還是保護的是一個人，做的都是同一件事——在中間留一層，擋住通過。
Wiktionary, entry 'insulate' (verb), packet source_ref kaikki:3f6f69a190036ae4:822697335
Two branches
包一層，擋住熱、電、聲音
這一支就是核心畫面本身，看得見也摸得到：牆裡的材料、水管外的包覆、電線外的橡膠。
verb · B2
To cover or wrap something in a material that stops heat, cold, electricity or sound from getting in or out. Houses, roofs, pipes, wires and walls are all insulated in this way.
隔絕（熱、冷、電、聲音）
把人跟難處隔開
同一層牆，只是這次擋的不是熱和電，而是壞消息、物價、批評。牆的邏輯一模一樣：麻煩還在外面，只是碰不到裡面的人。
verb · C1
To keep someone away from difficult or unpleasant experiences, or from something that would affect them, so that it does not reach them.
使不受影響、把…隔開保護
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
insulateverb/ˈɪnsjʊleɪt/
To separate, detach, or isolate.
To separate a body or material from others, e.g. by non-conductors to prevent the transfer of electricity, heat, etc.
insulateadj/ˈɪnsjʊleɪt/
Of pollen or spores, with superficial ornamentation grouped in circular or polygonal areas separated by grooves.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。