The spelling of the word "petras" can be explained using the International Phonetic Alphabet (IPA) which consists of symbols representing sounds in speech. The correct spelling of "petras" according to the IPA is /ˈpɛtrəs/. This means that the first syllable is pronounced with a short "e" sound, followed by a "tr" sound, and ending with a short "u" sound. The spelling of words can be important as it impacts understanding and effective communication.