trunko

Two senses, both of them the stripped middle of something. A trunko is the arbo's stem, the part left when you take away the branĉoj and the radikoj, and it is the human torso for the same reason: the korpo with the head and limbs removed. Latin truncus meant lopped, and both senses fall straight out of that.

Now the false seam, and it is English's fault rather than Esperanto's. English trunk does four jobs. Esperanto splits them across four words. The tree and the torso are trunko. The travelling chest and the boot of a car are kofro. A suitcase is a valizo, rank 1,395. And an elephant's trunk is a rostro, which is neither of the others and looks nothing like any of them. Packing your trunkon for a holiday says something anatomically alarming.

A third job the word does quietly. As in English, trunko serves for the main line of anything that branches: trunklinio for a trunk road or a main railway line, trunka nervo for a nerve trunk. That extension is safe, because it is the tree metaphor doing exactly what it does in English too.