To put it simply, the word "term" is another word for, well, word. Ultimately, literary terms are words used to describe devices used in literature. For example, we might call the main character of a story the protagonist. Protagonist is the literary term for main character. Similarly, antagonist would be the literary term for the opposing character in a story. As noted in the other answers, there are numerous literary terms.

There are many, many literary terms. Literary terms are used to describe how literature works, or how the author constructed the story or novel. For example, point-of-view is a literary term, meaning the perspective from which the story is written. In addition, narration is a literary term. Symbolism is a literary term. Symbolism refers to another of layer of meaning if a story that is more than the literal meaning.