The correct spelling of the word "Acratum" is actually "acrotom". The reason for the confusion is due to the pronunciation of the word. The IPA phonetic transcription for "acrotom" is /əˈkrəʊtəm/. The schwa sound at the beginning of the word can be easily mistaken for an "a" sound, and the omitted "m" at the end of the word can cause spelling errors. It's important to pay attention to the phonetic sounds and spelling rules when learning new vocabulary.