Like the previous answer of another member, Another example also can be : A dog = you dont know which dog it is The dog = you already know which dog it is. " The " is used when you're already certain/ know about something Hope it helps

The acticle "the" is used when you want to be specific when using a certain item (or in this case word). Examples of this could be: The dog, THAT dog, in French: Le Chien, ce chien (the=le) en espanol: El Perro Le Perro Hoped this helped!!