Caesura

Caesura (Latin, a cutting), the division of a metrical foot between two words. Such divisions must occur in certain places, by the laws of most Greek and Latin metres - in the third foot in a hexameter, in the fourth in an iambic line. As an illustration, in a line from one of the Attempts at Classic Metres in Quantity, published many years ago by Lord Tennyson -

Hexame | ters no | worse than | daring | Germany | gave us |

it would be a violation of classic rule if the two syllables which compose the third foot, "worse than," were one word or part of one word.