I
Basic unit of length in the metric system and the International System of Units .
In 1983 the General Conference on Weights and Measures decided that the accepted value for the speed of light would be exactly 299,792,458 metres per second, so the metre is now defined as the distance traveled by light in a vacuum in 1/299,792,458 second. One metre is equal to about 39.37 in. in the U.S. Customary System.
II
In poetry, the rhythmic pattern of a poetic line.
Various principles have been devised to organize poetic lines into rhythmic units. Quantitative verse, the metre of Classical Greek and Latin poetry, measures the length of time required to pronounce syllables, regardless of their stress; combinations of long and short syllables form the basic rhythmic units. Syllabic verse is most common in languages that are not strongly accented, such as French or Japanese; it is based on a fixed number of syllables within a line. Accentual verse occurs in strongly stressed languages, such as the Germanic; only stressed syllables within a line are counted. Accentual-syllabic verse is the usual form in English poetry; it combines syllable counting and stress counting. The most common English metre, iambic pentameter, is a line of 10 syllables, or 5 iambic feet; each foot contains an unstressed syllable followed by a stressed syllable. prosody .