A caesura is a pause or break within a line of poetry, often marked by punctuation like those you listed. It can be a full stop, a brief pause, or even just a slight hesitation.
Caesuras are often used to:
* Create emphasis: A pause before or after a significant word can draw attention to it.
* Control the rhythm: A caesura can break up the flow of the line and create a sense of rhythm.
* Reflect the meaning: The placement of a caesura can emphasize a particular idea or emotion.
Here's an example from Shakespeare's *Sonnet 116*:
> "Let me not to the marriage of true minds / Admit impediments."
The caesura after "minds" creates a pause before the word "admit," emphasizing its importance.