Único vs. singular
While both único and singular can be translated as unique in English, they are not interchangeable in Portuguese. They carry distinct nuances, with único focusing on exclusivity and singular on a remarkable or peculiar quality.
Único
A2The word único primarily means the only one or sole. It emphasizes that there is no other of its kind, focusing on exclusivity and quantity. It can also be used to mean exceptional or unparalleled.
Ele foi o único a terminar a maratona.
(He was the only one to finish the marathon.)
Este é o meu único par de sapatos.
(This is my only pair of shoes.)
A sua única motivação era o dinheiro.
(His sole motivation was the money.)
Cada floco de neve é único.
(Every snowflake is unique.)
Visitar as pirâmides foi uma experiência única.
(Visiting the pyramids was a unique experience.)
Singular
B2The word singular describes something as remarkable, extraordinary, peculiar, or unusual. It highlights a distinctive or strange quality that makes something stand out, rather than its exclusivity.
O escritor tem um estilo de escrita muito singular.
(The writer has a very singular writing style.)
Ela tem um senso de humor bastante singular.
(She has a rather singular sense of humor.)
O detetive notou um detalhe singular na cena do crime.
(The detective noticed a singular detail at the crime scene.)
A sua forma de ver o mundo era verdadeiramente singular.
(His way of seeing the world was truly singular.)
Aquele edifício antigo tem uma beleza singular.
(That old building has a singular beauty.)
Summary
In essence, use único when you mean the only one, emphasizing quantity or exclusivity. Use singular when you mean remarkable, peculiar, or out of the ordinary, emphasizing a special and distinctive quality. Something can be único without being singular (e.g., your only key), and something can be singular without being único (e.g., one of many peculiar paintings by an artist).