Tangerine is 橘子 orange is 橙子 The following is just my guess. We learned the word orange very early. And we are gradually getting used to use it to refer to all fruits that look like 橘子（kind of like a small orange). So 橙子 橘子 柠檬， a simple word to describe them， it would be "orange". Though， gradually as we grew up we know that's incorrect. But how could you expect a 7 or 8 year old child to know and master the pronunciation of "tangerine"? In that sense, "orange" seems to be way much easier to address 橘子🍊.

"橘子", usually we also call it "桔子", is easy to peel off (by hand), easy to seperate into petals. 易剥皮易分瓣 Another fruit called "橙子“, looks more like a ball, not easy to peel off, need a kninf usually, not easy to seperate into petals. 不易剥皮不易分瓣

橘子肯定不是orange。orange是橙子。橘子是mandarin。tangerine原名叫做tangerine orange。橘子是原产于中国的，第一次进入欧洲是从 Tangier, Morocco，因此被叫成从来自tangier的橙子，其实它是来自中国的橘子。因此后来把橘子叫成“mandarin”。 在四川，橘子（一般写成桔子，桔是橘的俗体字）和橙子是完全不同的两种水果，而且就算是桔子和橙子还要分成不同的橘子和不同的橙子。最有名的就是脐橙。现在搞杂交，有些品种我已经不知道叫什么了。

I don't know if orange has multiple meanings in English context, but Chinese people indeed thought that word refer to either 橘 or 橙.

It exactly means tangerine and orange normally refers to 橙子.