1.
Preparatory actions are done before doing something else as a form of preparation or as an introduction.
At least a year’s ~ work will be necessary before building can start.
= preliminary
ADJ: usu ADJ n
2.
If one action is done ~ to another, it is done before the other action, usually as preparation for it. (FORMAL)
Sloan cleared his throat ~ to speaking...
PREP-PHRASE