Prefatory and Prodromic

Prefatory adjective - Coming before the main part or item usually to introduce or prepare for what follows.

Prodromic and prefatory are semantically related. in prefatorial topic. In some cases you can use "Prodromic" instead an adjective "Prefatory". rare substitute

Prodromic adjective - Symptomatic of the onset of an attack or a disease.

Prefatory and prodromic are semantically related. Sometimes you can replace term "Prefatory" with "Prodromic", this adjectives are similar.