mē^trum — Lewis & Short
mē^trum, i, n., = me/tron,
I 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.