something that comes before a more important action or event
prelude - introduction
When something precedes or acts as an introduction for something much bigger, it can be called a ‘prelude’. Most commonly seen in written English in relation to politics or business, particularly print media. In a more specialized sense, this term is also used in classical music to refer to a short piece for the piano or organ, particularly one played before a church ceremony or longer composition.
We hope that the agreement we reached with that company will be a prelude to much bigger business between us in the future.
Bonuses have been frozen this year, but staff needn’t worry about that being a prelude to job-cuts. Our financial situation is not as bad as that.
The politician’s meet and greet with local dignitaries was just a prelude to the big speech she was giving in the town later that evening.