地面與建築物往下沉
這一家就是核心畫面本身，看得見、量得出來。土被泡軟、地下水被抽走，上面的東西就慢慢往下坐。其他幾家可以想成是從這個具體動作長出來的說法。
verb · C1
If a building, a road, or an area of ground subsides, it slowly sinks down to a lower level than it was at before.
下陷／沉降
核心畫面
Picture something that was up coming slowly back down to a flat, quiet level: a swollen piece of ground, a wall of flood water, a hard wind, a wall of noise, a hot temper. Subside is that downward settling. Two things stay true every time. It happens by itself, with nobody pushing it down, which is why the verb never takes an object. And it happens slowly, so you are usually looking at the stretch of time just after the highest point.
可以想成：本來鼓起來、撐高的東西，慢慢往下坐回去。地面往下沉、水位往下退、風勢往下走、痛和怒氣往下降——在英文裡都是…更多收起
可以想成：本來鼓起來、撐高的東西，慢慢往下坐回去。地面往下沉、水位往下退、風勢往下走、痛和怒氣往下降——在英文裡都是同一個動作。有兩件事每次都成立。第一，這個往下不是被誰壓的，是它自己降回平常的高度，所以後面永遠不接受詞。第二，速度總是慢的：先到最高點，然後一點一點回去。From the word’s history
Wiktionary traces subside to Latin subsīdō, glossed there as to settle, subside — a word about sinking down and coming to rest. Every modern use keeps that picture, whether the thing sinking is ground, water, weather or feeling.
Wiktionary 說 subside 來自拉丁文 subsīdō，意思是「沉下去、安定下來」。今天不管沉下去的是地面、水、風還是情緒，畫面都還是同一個：往下，然後靜下來。
Wiktionary, English 'subside' (packet etymology_text; source_ref kaikki:3f6f69a190036ae4:668043596:30210)
Three branches
天氣與水回到正常
水位和風勢都有「高度」。漲起來、吹起來是高點，之後慢慢降回平常的樣子，就是同一個往下坐的動作，只是這次沉下去的是水和空氣。
verb · C1
If water, especially flood water, subsides, it slowly drops back to its normal level, or slowly drains away into the ground.
（水）退去／水位下降
聲音與情緒平息
把同一個往下的畫面放到看不見的東西上。笑聲、痛、怒氣也像是會鼓起來的東西，鼓到最高之後自己慢慢降回去，沒有人把它壓下來。
verb · C1
If a feeling, a pain, a sound, or another strong thing subsides, it slowly becomes weaker and weaker, until it stops or comes back to a normal, quiet level.
平息／消退