Preliminary and Prodromic

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

Prodromic and preliminary are semantically related. in precursive topic. In some cases you can use "Prodromic" instead an adjective "Preliminary". rare substitute

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

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