frambo

One root, nothing inside it. Frambo does not come apart. There is no fram-, no -bo, and it has no relation to frazo or to anything else in the course. It is a borrowed plant name with an -o on the end, and the only work you have to do is remember it.

The fence, and it is a real one: frago against frambo.Frago at rank 1,864 is a strawberry. Frambo is a raspberry. They share the first three letters, they sit next to each other on the stall, they go into the same cake, and learners mix them up constantly. There is no clever mnemonic in the etymology to save you, because the two words come from entirely different places - frago is Latin fragum, frambo is Frankish through French - and the resemblance is pure accident.

The one hook that helps: the French pair is fraise and framboise, and framboise is the longer word for the longer Esperanto word. If you know any French at all, that is enough.

Round out the berry shelf while you are here: vinbero, a grape, is literally a wine-berry and does come apart. Mirtelo is a bilberry, rubuso a blackberry, ribo a currant. Note that vinbero is the only compound in that list: Esperanto borrowed a separate root for nearly every berry, because every European language already had one and there was nothing to gain by inventing.

And a small oddity of the frequency list. The bare root bero, a berry, does not have its own page in this course even though vinbero does, which is a gap rather than a decision. It exists, it means berry, and frambo is one.