What is crase?

Crase is a term used in French grammar to indicate the contraction of the preposition "à" with certain words, such as articles and pronouns. It is indicated by placing an apostrophe between the two words. For example, "à le" becomes "au", "à les" becomes "aux", and "à la" becomes "à l' " when the following word begins with a vowel. Crase is commonly used in spoken and written French, and is an important aspect of the language's grammar and syntax.