Correct spelling for the English word "rimula" is [ɹˈɪmjʊlə], [ɹˈɪmjʊlə], [ɹ_ˈɪ_m_j_ʊ_l_ə] (IPA phonetic alphabet).
A minute slit or fissure.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "rimula" does not have a widely acknowledged etymology. It appears to be a rare and uncommon term without a definite historical background or established origin.
However, it is worth noting that "rimula" bears similarities to the Latin word "rimula" or "remula", which means small oar or paddle used in a boat. This Latin term might have inspired the creation of the word "rimula" in a modern context, but this connection is speculative and not supported by concrete evidence.