The single white star in the flag’s blue triangle symbolizes the Commonwealth of Puerto Rico. The corners of the triangle represent the republican form of government of the island with its three independent branches: the Executive, the Legislative and the Judicial. The three red stripes symbolize the blood that feeds the three branches of the government and the two white stripes symbolize the freedom of man and the rights of the individual that keep the three branches of government in check.
The Puerto Rican flag was adopted on July 25, 1952, as an official emblem of the Commonwealth of Puerto Rico, when the island also adopted its own constitution.