What do we call a motive that is repeated immediately on the same note?

The term used to describe a motive that is repeated immediately on the same note is "Repetition." In musical composition, repetition involves the exact restatement of a musical idea, phrase, or motif without any change in pitch or rhythmic structure.

This concept is important in music as it can create familiarity and strengthen thematic material within a piece. When a motive is repeated exactly, it emphasizes the idea and allows listeners to engage more deeply with the music. While other options like sequence and imitation involve variation or transformation of the original material, repetition maintains the integrity of the motive as it appears again in its original form. An ostinato, on the other hand, typically refers to a repeated pattern that can be rhythmic, melodic, or harmonic but is not necessarily confined to the same note as in a straightforward motive repetition.