Parallel structure is the use of matching grammatical patterns in nearby words, phrases, or lines. In poetry, it can create balance, rhythm, emphasis, and a sense of deliberate order, especially when repeated structures build from one line to the next.
Poets often use parallel structure to link ideas and make a passage feel unified, memorable, or forceful.
Example
I came with winter in my coat,
I came with silence in my hands,
I came with hope still beating warm.