鞭毛

biānmáo - flagellum

I'm surprised that I didn't think of including this word earlier given that its what I spend most of my time working on. Like many Chinese words, it has a similar etomology to the English word: it means 'whip hair', whereas the English word comes from the same origin as the word 'flagellate'.

我研究鞭毛。
I research flagella.