Zeitgeist is a German language expression literally translated: Zeit, time; Geist, spirit, meaning "the spirit of the age and its society". The word zeitgeist describes the intellectual, cultural, ethical and political climate, ambiance and moral of an era or also a trend.
"Of Issachar, men who had understanding of the times, to know what Israel ought to do…" I Chronicles 12:32
For the Church to be relevant we need to understand the times that we are living in. As the Church we're going to discover more and more that relevance is more about the Church acting in spite of the trends rather than living according to the trends. We're said to be living in a postmodern era. Read more about the Postmodern Crackup by Charles Colson.