metre Symbol m. The SI unit of length that is equal to 39.37 inches. It is formally defined as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. This definition, adopted by the General Conference on Weights and Measures in October 1983, replaced the 1960 definition based on the krypton lamp, i.e. 1 650 763.73 wavelengths in a vacuum of the radiation corresponding to the transition between the levels 2p¹⁰ and 5d⁵ of the nuclide krypton-86. This definition replaced the older (1927) definition of a metre based on a platinum-iridium bar of standard length.

metre (symbol m) SI unit of distance. Conceived as being a ten-millionth of the surface distance between the North Pole and the Equator, it was formerly defined by two marks on a platinum bar kept in Paris. It is now defined as the length of the path travelled by light in a vacuum during 1/299,792,458 of a second. One metre equals 39.3701 inches.

metre1, U.S. meter form of poetic rhythm, metrical form, verse. XIV. — (O)F. mètre — L. metrum — Gr. métron, f. IE. *mḗ- MEASURE + instr. suffix. Also in comps. hexameter, pentameter, etc.
So metrical pert. to metre XV; relating to measurement XVII. — L. metricus — Gr. metrist XVI. — medL. metrista.

metre. Term used of regular succession of rhythmical impulses, or beats, in poetry and mus., e.g. 3/4 and 6/8 being described as different kinds of metres. Rhythm is no longer accepted as a sufficiently precise definition, metre being considered as the basic pulse and rhythm as the actual time-patterns of the notes within a measure. E.g., in 3/4 the 3 beats—strong, weak, weak—are metrical, while the time-values of the notes actually heard are the rhythm.

metre In poetry, a regular rhythmic pattern. It imposes a regular recurrence of stresses, typically dividing a line into equal units called metrical feet. The most commonly used metrical feet are anapaest, dactyl, iamb, and trochee. The metre of a poem is described according to the kind and number of metrical feet per line: for example, iambic pentameters have five iambs per line.