a measure; in partic., a poetical measure, metre; a verse (post-Aug.): rhythmi, id est numeri, spatio temporum constant: metra etiam ordine: ideoque alterum esse quantitatis videtur, alterum qualitatis, Quint. 9, 4, 46: metri necessitate cogi, id. 8, 6, 17; 1, 6, 2: metri causā, Gell. 4, 17, 9: Tibulli, i. e. elegiac metre ,Mart. 4, 6, 4: exceptis metris Vergilii, i. e. verses ,Col. 3, 10, 20 dub.