to gradually get closer to sb/sth that is moving or making progress in an activity :
The police car was gaining ground on the suspects.
They needed to make up ground on their competitors.
to gradually get closer to sb/sth that is moving or making progress in an activity :
The police car was gaining ground on the suspects.
They needed to make up ground on their competitors.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005