An address to an object or person not present is called an "apostrophe." It is a figure of speech in which the speaker directly addresses someone or something that is not present or cannot respond. This can be a person, a thing, an idea, or an abstract concept. Apostrophe is often used in poetry or literature to add emotional intensity or create a dramatic effect. It is commonly used to express strong feelings of love, anger, or grief towards something that cannot respond.