Accompaniment case is a grammatical or syntactic construction in poetry where a secondary element—often a noun or phrase—functions not as the subject or object but as an accompanying or contextual modifier that enriches the primary action or image; this case subtly deepens thematic texture by embedding relational context within the verse, such as “he walked, his shadow trailing,” where “his shadow” serves as the accompaniment case enhancing mood and spatial awareness.

Accompaniment case: Refers to grammatical or musical structures that provide support or accompaniment; in poetry, it may describe syntax or phrasing that highlights a supportive role of surrounding words.