In poetry and music, an anacrusis (from Ancient Greek: ἀνάκρουσις, anákrousis, meaning "pushing up") is a short introduction. In music, it is also called a pickup beat or fractional pick-up, which is a note or group of notes that comes before the first strong beat in a musical measure.

An anacrusis is one or more syllables or notes that appear before the first foot of a poetic line (or the first syllable of that foot) in poetry. In music, it is one or more notes that appear before the first beat of a measure, but it is not part of the previous section, phrase, or line.

Poetry

In poetry, a group of syllables that are not part of the regular meter at the start of a verse are called anacrusis (from Ancient Greek: ἀνάκρουσις, meaning "pushing up"). This term describes "an extra, unstressed syllable or syllables before the first stressed syllable of a line." The technique appears in Old English poetry and in lines of iambic pentameter, where it creates a variation that may make the line seem like it follows trochaic meter at first glance. For example, in the fourth line of William Blake's poem "The Tyger" (with punctuation updated for modern use), the anacrusis is shown in italics:

Tyger, Tyger, burning bright In the forests of the night, What immortal hand or eye Could frame thy fearful symmetry?

The poem follows trochaic tetrameter, a meter where the first syllable of each line is typically stressed. However, the fourth line begins with the extra unstressed syllable "Could."

Anacrusis is an optional, unstressed syllable that comes right before the first stressed syllable at the start of a verse. As an element outside the regular meter, it does not form its own metrical unit. Instead, it is added to the following stressed syllable and is counted as part of the stressed syllable's pattern.

Music

The term "anacrusis" was first used by Westphal. An anacrusis is one or more unstressed notes that come before the first strong beat in a musical section. In music, an anacrusis (also called a pickup or fractional pickup) is a note or group of notes that appear before the first downbeat in a measure of a musical phrase. It is the part of a musical group that leads up to the strongest beat in that group. Repeating an anacrusis (using the same pattern before every measure or every other measure) is a common way to emphasize the first beat, helping to make the rhythm clearer.

The word "anacrusis" comes from poetry terms. Anacrusis can involve small details like rhythm and how music is phrased, or it can relate to larger aspects like musical structure (such as when it is used repeatedly).

A melody often begins with an anacrusis. An anacrusis is an unstressed note or group of notes that come before the first stressed note in a musical phrase (a short section of music). The stressed note is found in the first complete measure of the music.

An anacrusis is a grouping that people perceive based on how a piece of music is written. This grouping may be created by the timing of notes that happen just before the first strong beat of a phrase.

Although an anacrusis is part of a musical phrase, it is not included in the main part of the phrase (which starts with the first strong beat and ends with the last beat). Instead, it comes before the phrase, which is why it is sometimes called "Auf takt" in German, meaning "upbeat." In a series of phrases, an anacrusis may be heard as something that happens between two phrases, not as part of the ending of one phrase or the beginning of the next.

When a melody starts with an anacrusis, the way the music is phrased and the way notes are shaped must focus on the first important note of the melody. If the focus is on the note that comes next, the anacrusis naturally leads to it with the right musical expression.

The direction of beats is important in music. The strong beat of a measure or phrase is the beginning; it pushes the music forward, so the sound should rise and move in a way that shows direction. The anacrusis leads to the strong beat but does not have the same sudden, powerful sound. It prepares the listener for the strong beat.

In other cases, the term "anacrusis" is used to describe a part of a musical phrase between the first strong beat (the "head") and the last beat (the "foot") where a grouping is perceived from an upbeat to a downbeat, especially to the phrase's ending beat.

An anacrusis, or upbeat, seems like a continuation that is not tied to a previous start. It feels unanchored and, in some cases, appears to come from nowhere. An anacrusis points forward; it is anticipatory and looks toward a future event.

An anacrusis is an incomplete measure that allows a piece of music to start on a beat other than the first. If an anacrusis is present, the first full measure after it is labeled as measure 1. In Western musical notation, it is often recommended to leave out the same number of beats from the final measure of a piece or before a repeat sign to ensure the total length of the piece is a whole number of measures. This final partial measure is called the complement. However, an anacrusis can sometimes last for an entire measure.

Other fields

In academic publishing, the term is sometimes used in some articles to introduce an idea that comes after the abstract and before the main introduction.