(~s)
If you refer to an action, or the result of an action, as a ~, you admire it because it is an impressive and difficult achievement.
A racing car is an extraordinary ~ of engineering.
N-COUNT approval
(~s)
If you refer to an action, or the result of an action, as a ~, you admire it because it is an impressive and difficult achievement.
A racing car is an extraordinary ~ of engineering.
N-COUNT approval
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012