rimo

Esperanto has a rhyme problem, and this is the word for talking about it. Every noun ends in -o, every adjective in -a, every verb tense in -as, -is or -os. So rhymes are everywhere and almost all of them are free, which makes them worthless. Rhyming kantas with dancas is rhyming two grammatical endings, not two words. Esperanto poets named the vice early: adasismo, from -adas, and it is the first thing anybody learns not to do. Getting the full picture, including elision and the l' apostrophe, is worth a detour to poetic Esperanto.

So a real rhyme has to reach into the root. Koro and floro rhyme on -oro, which is root material plus the ending, and that counts. Muŝo and buŝo rhyme properly, which is why Zamenhof put them in a proverb. The technical vocabulary is small and regular: rimi is to rhyme, rima rhyming, rimaranĝo the rhyme scheme, senrima blank or unrhymed, rimvorto a rhyme word, rimlisto a rhyming dictionary. Riĉa rimo is a rich rhyme, matching more than the minimum.

Rhyme is not rhythm, though the two are the same word underneath. Ritmo is the beat, the pattern of stressed and unstressed syllables, and in Esperanto the stress is always on the second-to-last syllable, which makes the metre unusually predictable and the poet's job unusually hard. Rimo is only the matching of sounds at the line end. Both descend from Greek rhuthmos, split apart in Old French, and Esperanto imported them separately as two roots, so the ancient relationship is real and completely useless for building either from the other.