"Gonimium" is a very rare word that refers to a female reproductive organ in certain marine invertebrates. The spelling of this word can be explained using the International Phonetic Alphabet (IPA) as: /ɡɒˈnɪmiəm/ - the initial letter "g" is pronounced as "ɡ", the second letter "o" as "ɒ", the following letters "n-i-m-i" as "nɪmi", and the final letter "u-m" as "əm". The use of IPA helps in accurately representing the sounds of the word and its overall pronunciation.