Learner's definition of INROAD
— used to describe a situation in which someone or something becomes more successful or important often by making someone or something else less successful
— usually plural
— usually used with make
Despite the recent inroads made by competitors in the industry, the company is still doing well.
The party hopes to make serious inroads in Congress. [=the party hopes that many more of its members will be elected to serve in Congress]
The sport is making inroads in the U.S. [=it is becoming more popular in the U.S.]