The spelling of the word "onagon" is incorrect. In fact, there is no such word in the English language. Perhaps you were referring to "octagon", which is spelled [ɑk.tə.ɡɑn] using the International Phonetic Alphabet (IPA). This word refers to a shape with eight sides, such as a stop sign. Spelling correctly not only helps you communicate effectively, but it also reflects positively on your intelligence and attention to detail.