Puerto Rican cuatro

The Puerto Rican cuatro (Spanish: cuatro puertorriqueño) is the national instrument of Puerto Rico. It belongs to the lute family of string instruments, and is guitar-like in function, but with a shape closer to that of the violin. The word cuatro means "four", which was the total number of strings of the earliest Puerto Rican instrument known by the cuatro name.

The current cuatro has ten strings in five courses, tuned, in fourths, from low to high B3 B2♦E4 E3♦A3 A3♦D4 D4♦G4 G4 (note that the bottom two pairs are in octaves, while the top three pairs are tuned in unison), and a scale length of 500–520 millimetres.