1. progress; an advance: "an important way to make inroads in reducing spending"
▪ an instance of something being affected, encroached on, or destroyed by something else: "serious inroads had now been made into my pitiful cash reserves"
2. a hostile attack; a raid.
Word Originmid 16th century (in inroad (sense 2 of the noun)): from in + road (from an early use in the sense ‘riding’).
