If something is tangential, it touches your subject only at the edge — it is connected, but not in the way that matters.

If something is tangential如果某樣東西是 tangential, it touches your subject only at the edge它只在邊緣碰到你的主題 — it is connected但它是有關的, but not in the way that matters只是不是重要的那種關聯。

You say it about remarks, questions, information, evidence, or a whole discussion: 'a tangential remark', 'the point is tangential to our argument'. Note that pattern: tangential TO something.

about remarks, questions, information, evidence, or a whole discussion對於一句話、一個問題、一則資訊、一項證據，或整場討論 you say it你都可以這樣說：'a tangential remark'「一句離題的話」、'the point is tangential to our argument'「這個論點跟我們的論證只沾到邊」。Note that pattern要注意這個句型：tangential TO something是 tangential to 某樣東西。

It is not a rude word, but it is a polite way of saying 'this is off the point', so people use it in meetings and academic writing when they want to move on without embarrassing anyone. It is formal — you would not say it to a friend, where you would say 'that's a bit off-topic' or 'that's beside the point'.

It is not a rude word它不是一個沒禮貌的字, but it is a polite way of saying 'this is off the point'而是「這離題了」的委婉說法, so人們因此 people use it in meetings and academic writing在會議和學術寫作裡用它 when they want to move on without embarrassing anyone想跳過這個話題又不讓人尷尬的時候。It is formal它是正式用語 — you would not say it to a friend跟朋友講話不會這樣說, where you would say 'that's a bit off-topic' or 'that's beside the point'那種情況你會說 that's a bit off-topic 或 that's beside the point。

Two things to keep straight. First, tangential does not mean unrelated. If something is completely unconnected you say 'irrelevant'; tangential means there IS a link, just a thin one at the edge.

Two things to keep straight有兩件事要分清楚。First第一, tangential does not mean unrelated tangential 不等於「無關」。If something is completely unconnected如果完全沒有關係 you say 'irrelevant'你會說 irrelevant；tangential means there IS a link而 tangential 是指「確實有關聯」, just a thin one at the edge只是那關聯很薄、在邊緣而已。

Second, people also say a person is tangential, or 'goes off on a tangent', meaning they keep drifting from one side-topic to another — that is about the speaker, not the fact.

Second第二, people also say a person is tangential人們也會說一個人是 tangential, or 'goes off on a tangent'或說他 goes off on a tangent, meaning they keep drifting from one side-topic to another意思是他一直從一個支線話題飄到另一個 — that is about the speaker, not the fact這說的是講話的人，不是事情本身。

In maths and physics the word keeps its literal meaning: touching a curve at one point, or acting along the direction of a tangent (tangential velocity, tangential force). The picture behind the everyday meaning comes from there — a line that meets a circle at one single point and then heads off in its own direction. That image is worth holding on to; it explains the word better than any definition.

In maths and physics在數學和物理裡 the word keeps its literal meaning這個字保留字面上的意思：touching a curve at one point碰到曲線上的一個點, or acting along the direction of a tangent或沿著切線方向作用 (tangential velocity「切線速度」, tangential force「切線力」)。comes from there日常意思背後的畫面就是從這裡來的 the picture behind the everyday meaning — a line that meets a circle at one single point一條線碰到圓上的一個點 and then heads off in its own direction然後就往自己的方向去了。That image那個畫面 is worth holding on to值得記住；it explains the word better than any definition它比任何定義都更能說明這個字。