What is a Basilica?
"Basilica" is a title assigned to certain churches by the Holy See because of their antiquity, dignity, historical importance, or significance as centers of worship.
There are two types of basilica- Major and Minor. Major Basilicas (St. Peter's, St. Paul Outside the Walls, St. John Lateran, St. Mary Major- all in Rome; St. Francis in Assisi) contain the papal altar and have holy doors which are opened in Jubilee Years (such as the 1987-88 Marian Year). Minor Basilicas are other churches which receive the title because of the factors listed above.
A basilica is intimately linked to the Chair of Peter. It's to be a center of special liturgical and pastoral ministry. For example, Mass is generally offered in a basilica several times a day, frequent confessions are scheduled, basilicas are the destinations of pilgrims who wish to acknowledge by their coming the universal nature of the Church founded upon the rock of Peter, the Pope. The liturgical documents call for great solemnity and perfection in the celebration of mass at a basilica- requiring that especially on holy days one or more of the Masses be in Latin. When such Masses are sung, they are to use Gregorian melodies or sacred polyphony. Another activity proper to a Basilica is the holding of programs that make known the documents expressing the mind of the Pope and the Magisterium of the Church.
St. James was the 34th church in the United States to be designated as a Minor Basilica.