Anacrusis

In poetic and musical meter, and by analogy in publishing, an anacrusis (from ἀνάκρουσις, anákrousis, literally: 'pushing up', plural anacruses) is a brief introduction (distinct from a literary or musical introduction, foreword, or preface). It is a set of syllables or notes, or a single syllable or note, which precedes what is considered the first foot of a poetic line (or the first syllable of the first foot) in poetry and the first beat (or the first beat of the first measure) in music that is not its own phrase, section, or line and is not considered part of the line, phrase, or section which came before, if any. In poetry, a set of extrametrical syllables at the beginning of a verse is said to stand in anacrusis (ἀνάκρουσις "pushing up"). "An extrametrical prelude to the verse," or, "extrametrical unstressed syllables preceding the initial lift." The technique is seen in Old English poetry, and in lines of iambic pentameter, the technique applies a variation on the typical pentameter line causing it to appear at first glance as trochaic. Below, the anacrusis in the fourth line of William Blake's poem "The Tyger" (with punctuation modernized) is in italics: Tyger, Tyger, burning bright In the forests of the night, What immortal hand or eye Could frame thy fearful symmetry? The poem is in trochaic tetrameter, in which the first syllable of each line is expected to be stressed, but the fourth line begins with the additional unstressed syllable "Could". Anacrusis is an optional unstressed syllable that appears immediately before the first lift at the beginning of the verse. As an extrametrical element, it does not constitute an independent metrical position; rather, added as a supplement to the following stressed syllable, it counts as part of the lift. Upbeat (music)The word anacrusis is introduced by Westphal ... The anacrusis merely consists of the unaccented note or notes which precede the first accent of any rhythmic division in a composition.