prodromal (adj.)

1640s, "a forerunner" (a sense now obsolete); by 1834 in pathology, "a prodromal symptom;" from French prodrome (16c.) and directly from Modern Latin prodromus, from Greek prodromos "a running forward, a sally, sudden attack," from pro "forward" (see pro-) + dromos "a running" (see dromedary). Related: Prodromata; prodromatic; prodromic; prodromous.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).