on Writing Forward:
We can classify most poetry into two groups: form poetry and free verse. Free verse is a style of poetry that doesn’t adhere to any structure; the poet is free to write lines and stanzas of varying lengths and meter, with or without rhymes.
Form poetry, on the other hand, adheres to a specific structure, a formula that drives the entire poem based on a set of established rules and patterns.
Chris The Story Reading Ape's Blog 