procesio

A procession: a line of people moving somewhere together, on purpose and usually slowly. Religious ones, funerals, carnival, a torchlit march to a monument. The word carries ceremony with it, so a procesio is never just a queue.

Now the near-pair, because it will catch you.Proceso is at rank 1520 and means a lawsuit or a process. Procesio is a parade of people. One extra i and you have gone from a courtroom to a church street, and the two words are related only in the sense that the same Latin verb procedere fathered both. If you say mi vidis longan proceson you have watched a trial drag on; longan procesion and you watched a march go past.

And the third one, which nobody warns you about.Procedo lands in this same chapter and means a procedure, the defined way of going about something. So the trio runs: procedo is the method, proceso is the unfolding (or the court case), and procesio is the crowd walking. Three separate roots in Esperanto, one Latin ancestor, no shared grammar between them. Learn them as three words, not as one word with endings.