extra-metrical

But only three lines of the eight have a feminine or trochaic ending, and all except the third have iambic or rising rhythm in the first foot; so that it is more simple and natural to consider the last syllable of the first, third, and seventh lines as extra-metrical, and call the rhythm iambic-anapestic, or rising.

The Principles of English Versification Paull Franklin Baum

'Say Not, the Struggle Naught Availeth.' the movement is clearly iambic, yet the first and third lines have an extra-metrical syllable at the end.

The Principles of English Versification Paull Franklin Baum

CAESURA, the classical term for a pause, usually grammatical and extra-metrical (i.e. not reckoned in the time scheme).

The Principles of English Versification Paull Franklin Baum

Could frame thy fearful symmetry? seems clearly to be trochaic; yet the last trochee of each line lacks its unstressed element, and the fourth line has an extra-metrical syllable, _Could_.

The Principles of English Versification Paull Franklin Baum

By itself the fourth line would be called iambic: in this context it is called trochaic with 'anacrusis,' i. e., with one or more extra-metrical syllables at the beginning. [

The Principles of English Versification Paull Franklin Baum