noun
: something beyond comprehension
railway operation is a closed book for many people — O.S.Nock
: something that resists clarification
a modern age in which the law is a closed book — B.N.Cardozo
noun
: something beyond comprehension
railway operation is a closed book for many people — O.S.Nock
: something that resists clarification
a modern age in which the law is a closed book — B.N.Cardozo
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012