Both Uses

prelude
in
Oliver Twist
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With this view he gave a kick at the outside, by way of prelude; and, then, applying his mouth to the keyhole, said, in a deep and impressive tone: 'Oliver!'†
Chpt 7 *
As Fagin stepped softly in, the professional gentleman, running over the keys by way of prelude, occasioned a general cry of order for a song; which having subsided, a young lady proceeded to entertain the company with a ballad in four verses, between each of which the accompanyist played the melody all through, as loud as he could.†
Chpt 26

Definitions:

(1) (prelude)
something that comes before and prepares for what follows; in music, a short piece that introduces a larger work or stands alone as a brief, expressive piece (often for piano)

In everyday use, a prelude is an event or action that leads up to something more important, like a small disagreement being a prelude to a larger conflict. In music, the word can mean a short opening piece (for example, before an opera scene) or a short, self-contained work, often written for piano or organ, that sets a mood.
(2) (meaning too rare to warrant focus)