The correct spelling of the word "stimac" is actually "stomach". The reason for this spelling difference is due to the English language's irregular spelling rules. The IPA phonetic transcription of "stomach" is /ˈstʌmək/. The initial "o" sound is represented by the letter 'o', the schwa sound in the second syllable is represented by the letter 'u', and the final "ch" sound is represented by the letters 'ch'. Therefore, we can conclude that the spelling of the word "stimac" is incorrect and the correct spelling is "stomach".