The spelling of the word "kyllosis" can be explained through its phonetic transcription. According to IPA, the word is pronounced as /kɪˈləʊsɪs/, with the stress falling on the second syllable. The "kyl" syllable is spelled using a "k" instead of a "c" to represent the hard /k/ sound. The letter "y" is used to represent the vowel sound /ɪ/ instead of the more common letter "i". Lastly, the ending "-osis" is spelled as "-os is" to represent the pronunciation with a distinct ending syllable.