ŝtipo

Say it out loud before anything else: ŝtipo is not ŝipo. One letter apart, and the two words could hardly be further apart in meaning: a ŝipo is a ship, a ŝtipo is a log. The pair is worse in the x-system than in real orthography, where sxipo and sxtipo differ by a single t buried in a consonant cluster, and worse again in speech if you are not separating the ŝ from the t. Esperanto has very few minimal pairs this cruel, so it is worth spending the ten seconds now.

What a ŝtipo actually is. The dictionary definition is a short thick piece of wood, which covers the log you throw on the fire, the chopping block, the billet and the fence post. It is not the material: that is ligno. It is not the standing tree, which is an arbo, nor the trunk, which is a trunko. A ŝtipo has been cut. The hakilo at rank 2,302 is the tool that makes one.

Two derivations you will meet, and one of them is grim. Ŝtiparo, with the collective -ar- this band uses three times over, is a stack of logs for a fire, and by an old and specific extension a funeral pyre or the pyre a condemned person was burned on. Ŝtiparumi is the verb for that execution. Ŝtipeto is a small piece of wood, a kindling stick. And ŝtipulo, with the person suffix, is a blockhead, which English arrives at from precisely the same picture.

A dead ŝtipo makes an archaic sense too. In older texts ŝtipo can mean a tree stump left in the ground. Modern usage prefers stumpo for that, and you will meet the old sense mostly in nineteenth-century prose, which is a fair description of half the corpus this frequency list was built from.