"إلا" is an Arabic word that translates to "except" or "but" in English. It is commonly used to indicate exclusion or limitation in a sentence. For example, in the phrase "كلهم جاءوا إلا محمد" (Everyone came except محمد), it shows that محمد did not come while others did. In Arabic grammar, "إلا" can also introduce exceptions in various contexts, such as in conditional sentences. It often requires specific grammatical rules, such as the use of the إلا clause, which can change the structure of the sentence. Understanding its usage is essential for mastering Arabic syntax and meaning.