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1670s, "action of marking off of verse in metric feet," from Late Latin scansionem (nominative scansio), in classical Latin, "act of climbing," noun of action from past participle stem of scandere "to climb" (see scan (v.)). From 1650s in English in literal sense of "action of climbing up."
the analysis and visual representation of a poem's metrical pattern. Adapted from the classical method of analyzing ancient Greek and Roman quantitative verse, scansion in English prosody employs a system of symbols to reveal the mechanics of a poem-i.e., the predominant type of foot (the smallest metrical unit of stressed and unstressed syllables); the number of feet per line; and the rhyme scheme. The purpose of scansion is to enhance the reader's sensitivity to the ways in which rhythmic elements in a poem convey meaning. Deviations in a poem's metrical pattern are often significant to its meaning.