What is the term for a temporary shift of the metric accents, where notes grouped in three switch to two or vice versa?

The term for a temporary shift of the metric accents, where notes grouped in three switch to two or vice versa, is known as hemiola. This phenomenon typically occurs in music when the rhythmic structure is altered, leading to a feeling of syncopation or changing the flow of the beat. In a hemiola, for instance, a section of music that is traditionally felt in a 3/4 pattern may momentarily be interpreted in a 2/4 feel, creating a unique tension and release within the rhythm. This transformation gives a lively, dynamic quality to the music, often highlighted in various musical genres, such as Baroque and folk music.

Understanding hemiola is crucial for musicians and composers, as it allows for creative rhythm manipulation and enriches the overall texture of a piece. Other concepts, while relating to rhythm and meter, do not capture this specific shift in accents.