The word "Mesymnicum" can be a bit tricky to spell. The correct pronunciation is /mɛsɪmˈnɪkəm/ and it is usually spelled with an "s" rather than a "c". The first syllable is pronounced with the short "e" sound, followed by the "s" and "i" sounds. The second syllable has the "m", "n", and "ɪ" sounds, with the stress falling on the second syllable. This word is not commonly used in English, but it might be helpful to know its correct spelling and pronunciation if you encounter it.