A natural pause or break in the middle of a line of poetry, instead of at the end of the line. For instance, there is a caesura in a poem by Robert Frost called "Mending Wall." The period between "side" and "I," like a wall, breaks the line in half and creates a natural pause. Compare this to the punctuation marks at the end of the lines, where we would expect them to be:
We wear our fingers rough with handling them.
Oh, just another kind of out-door game,
One on a side. It comes to little more:
There where it is we do not need the wall:
He is all pine and I am apple orchard.
