The acute accent is a diacritical mark that appears as a slanted line (´) placed above a vowel. It is commonly used in various languages, including Spanish, French, and Portuguese, to indicate a specific pronunciation or stress on that vowel. For example, in Spanish, the word "café" uses the acute accent to show that the last syllable is stressed. In addition to indicating stress, the acute accent can also differentiate between words that are otherwise spelled the same. For instance, in French, "a" (has) and "à" (to) are distinguished by the presence of the accent. This mark plays a crucial role in ensuring correct pronunciation and meaning in written language.