Structure
Line Break
Free verse poets (Whitman, Williams, Olson) theorised the line break as the primary unit of breath and meaning. It is the feature that most distinguishes poetry from prose.
Definition
The point at which a line of poetry ends — a fundamental compositional decision that controls rhythm, emphasis, and ambiguity.
Example
Plath: 'Dying / Is an art, like everything else. / I do it exceptionally well.' — the isolated 'Dying' amplifies its weight.