Interjections are short utterances that stand apart from the main grammar of a sentence and register an immediate response: delight, pain, surprise, grief, disgust, or invocation. In poetry, words such as “O,” “ah,” and “alas” can make the speaker seem present before the reader, as if the poem were spoken in the moment. They may also shape rhythm through pauses and bursts of sound. Because they condense emotion into a small verbal gesture, interjections are useful in lyric, elegy, prayer, song, and dramatic verse.

Interjections give a poem an audible, immediate voice and can interrupt a measured line with emotion. Their effect depends greatly on punctuation, placement, and whether the utterance feels sincere, comic, or theatrical.