Literary Devices
Literary elements are the universal constituents of literature and thus can be found in any written or oral story. Plot and character, for example, are necessary to story and are present in stories from every culture and time period.
Literary techniques, however, are not universal or necessary in the sense that not all works contain instances of them. Simile and irony are examples of literary techniques. While many poems contain similes, not all do. Simile, therefore, is a literary technique instead of a literary element.