In poetry, an anacrusis (Ancient Greek: ἀνάκρουσις "pushing up") is the lead-in syllables, collectively, that precede the first full measure.
In music, an anacrusis is the note or sequence of notes which precedes the first downbeat in a bar. In the latter sense an anacrusis is often called a pickup, pickup note, or pickup measure. Western standards for musical notation often include the recommendation that when a piece of written music begins with an anacrusis, the composer, copyist, typesetter, or printer should delete a corresponding number of beats from the written music's final measure in order to keep the number of measures in the entire piece at a whole number. The plural of anacrusis is anacruses (see Ancient Greek grammar (tables)#Suffixes of the nouns of the third declension).
| x | / | x | x | / | x | x | / | x | x | / | |
| Oh, | say, | can | you | see, | by | the | dawn's | ear | ly | light. . . |