Peter was not a member of a religious order.
There are several saints named Augustine. Please be specific.
The initials sometimes given after a saint's name indicate the religious order, if any, of the saint - O.P. - Order of Preachers (Dominicans), O.S.B. - Benedictines, O.S.F. - Franciscans, etc.
Because that is where St. Peter the Apostle was martyred.
The Church is called Saint Peters Basillica.
Saint Bernadette did not start a religious community.
Saint Andrew was the brother of Saint Simon Peter.
The scientific or taxonomic name would be Tilapia spp.
OP stands for Order of Preachers, another name for the Domican Order founded by St. Dominic.
There are several saints named Anthony so you need to be specific. However, most of the Anthonys received their name from either their parents or from the religious order they belonged to,
When a person enters a religious order they usually require that the person choose a new name to be used as a member. The name is usually that of a saint.
In most cases, a nun will choose her own new name when she enters the religious order. This name is often inspired by a saint or virtue that holds significance to the nun personally.
The Dominicans are a Roman Catholic, hence Christian religious order. There are both Male and Female Dominicans. Name derives from Saint Domenic.