CATHEDRALS

The chief church of a diocese, in which the bishop has his throne (cathedra) and close to which is his residence; it is, properly speaking, the bishop's church, wherein he presides, teaches, and conducts worship for the whole Christian community.
The word is derived from the Greek kathedra through the Latin cathedra, throne, elevated seat.

Acknowledgement: http://www.newadvent.org/cathen/03438a.htm

MONASTERIES

Monasteries are dwelling places for a community of persons, especially monks following the Christian faith, who live a life of partial or complete seclusion and are bound by vows to lead a religious life. Churches are a part of the Monastery where the monks spend their time in meditation and prayer. The monastery is a self sufficient place and promotes service to the community. A monastery may be an Abbey or a Priory.

Picture taken from : http://ogleearth.com/2006/07/coptic-monasteries-in-egypt/

Acknowledgement: http://www.thefreedictionary.com/monastery

CHURCH DEFINATION

The word 'church' is translated from the Greek word 'Ekklesia' which means the 'called out ones'. The church is a place of worship for the followers of Jesus Christ. The Merriam Websters Dictionary defines churches as a building for public and especially Christian worship.

Acknowledgement:   http://hell-fact-or-fable.com/2010/04/from-where-did-we-get-the-word-church/