prelude >> /ˈprɛlˌ(j)ud/
Definition: [transitive verb] Serve as a prelude or introduction to.
Example: the bombardment preluded an all-out final attack
Definition: [noun] An action or event serving as an introduction to something more important.
Example: education cannot simply be a prelude to a career
Definition: [noun] An introductory piece of music, most commonly an orchestral opening to an act of an opera, the first movement of a suite, or a piece preceding a fugue.
Example: His surviving output consists solely of instrumental music, including organ preludes and fugues, concertos for two harpsichords, and trio sonatas, much of it strongly influenced by Bach.