The three blue stripes refer to the three old divisions of the island, and the two white stripes represent the purity of the independence ideal. The red triangle stands for equality, fraternity, and freedom, and the white star represents the new republic.
History
Designed in 1849 by Narciso López, an anti-Spanish exile in New York. It became the official national flag in 1902 upon independence from the US.
Construction
A 1:2 ratio. Five alternating horizontal stripes (three blue, two white) and a red equilateral triangle at the hoist containing a white five-pointed star.