"L'" is a French definite article used before singular nouns that begin with a vowel sound or a mute 'h'. It is a contraction of the article "le" or "la," which means "the" in English. This form helps with the flow of speech and is commonly used in everyday language. In French grammar, using "L'" correctly is essential for proper sentence structure. For example, one might say "L'ami" to mean "the friend" or "L'école" for "the school." Understanding this article is crucial for learners of the French language as it aids in forming coherent sentences.