Root diameter of thread
[机] 齿根直径, 螺旋纹底直径
🧩 词语组成解析
root
[rut]
n. 根，根源;原因，本质;祖先;[乐]和弦基音;
vt. 使生根;使固定;根源在于;欢呼，喝彩;
vi. 生根;根除;
of
[əv]
prep. 关于;属于…的;由…制成;
aux. 助动词 [非标准用语、方言] =have [主用于虚拟语气];
thread
[θrɛd]
n. 线;线索;线状物;螺纹;
vt. 穿成串;将（针、线等）穿过…;用…线缝;给…装入（胶片、狭带、绳子）;
🗣️ 情景例句
Hello, Miss Wang. I'm fine, and you?
喂，王小姐，我很好，你呢？
There is much to be said on both sides.
公说公有理，婆说婆有理。
At first I thought I'd done the right thing, but I soon realized that I'd made a mistake.
开始我以为我做对了，但是很快就发现自己犯了个错误。