Webster Dictionary(0.00 / 0 votes)Rate this definition: 1  Hypo-. a prefix signifying a less quantity, or a low state or degree, of that denoted by the word with which it is joined, or position under or beneath. 2  Hypo-.
Confidence votes 25. St Patrick's Cathedral in New York City. ***Actually, the Basilica of the National Shrine of the Immaculate Conception in DC is larger than St. Patrick's in NYC. The National Shrine is the largest Roman Catholic church in the U.S., and one of the 10 largest Roman Catholic churches in the world.
The country where the membership of the church is the largest percentage of the population is Vatican City at 100%. According to the Census of the 2017 Annuario Pontificio (Pontifical Yearbook), the number of Catholics in the world was about 1.285 billion at the end of 2015. Conflicting numbers can be found in 2013 research conducted by Brazilian polling institute Datafolha.