An open syllable is the antonym of the closed syllable. A closed syllable is a syllable that ends with a consonant sound, while an open syllable is a syllable that ends with a vowel sound. In an open syllable, the vowel sound is usually long, meaning it is pronounced for a longer duration. Conversely, in a closed syllable, the vowel sound is typically short. For instance, the word "hat" has a closed syllable, while the word "hi" has an open syllable. Understanding the difference between open and closed syllables can help improve your reading and spelling skills.