"Unchurched" means, in the broad sense, people who are not connected with a church

Church Body

A local church is a Christian religious organization that meets in a particular location. Many are formally organized, with constitutions and by-laws, maintain offices, are served by pastors or lay leaders, and, in nations where this is permissible, often seek seek non-profit corporate status...

. In research on religious participation, it refers more specifically to people who do not attend worship services. The Barna Group defines the term to mean "an adult (18 or older) who has not attended a Christian

Christianity

Christianity is a monotheistic religion based on the life and teachings of Jesus as presented in canonical gospels and other New Testament writings...

 church service within the past six months" excluding special services such as Easter

Easter

Easter is the central feast in the Christian liturgical year. According to the Canonical gospels, Jesus rose from the dead on the third day after his crucifixion. His resurrection is celebrated on Easter Day or Easter Sunday...

, Christmas

Christmas

Christmas or Christmas Day is an annual holiday generally celebrated on December 25 by billions of people around the world. It is a Christian feast that commemorates the birth of Jesus Christ, liturgically closing the Advent season and initiating the season of Christmastide, which lasts twelve days...

, wedding

Wedding

A wedding is the ceremony in which two people are united in marriage or a similar institution. Wedding traditions and customs vary greatly between cultures, ethnic groups, religions, countries, and social classes...

s or funeral

Funeral

A funeral is a ceremony for celebrating, sanctifying, or remembering the life of a person who has died. Funerary customs comprise the complex of beliefs and practices used by a culture to remember the dead, from interment itself, to various monuments, prayers, and rituals undertaken in their honor...

s. Barna reports that there were 75 million "unchurched people" in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 as of 2004.

Many books and articles have been written by Western church leaders to address the decline of Christendom

Christendom

Christendom, or the Christian world, has several meanings. In a cultural sense it refers to the worldwide community of Christians, adherents of Christianity...

 in a post-modern world and how the assumption that new attendees have knowledge of basic Christian teachings is no longer reliable.