Similar words
centenar
Worth distinguishing: centenar is a hundred (of anything); siglo is a century, specifically a hundred years.
Similar in other languages
French
siècle
siècle is the French word for the same thing — both mean "century."
Portuguese
século
século is the Portuguese word for the same thing — both mean "century."
Practice
1 What does siglo mean?
century
2 Fill the gap: Estamos en el ___ veintiuno.
Full sentence: Estamos en el siglo veintiuno. (We are in the twenty-first century.)
3 Which fingerprint chart matches siglo?
siglo: neutral register, core frequency, general domain, neutral connotation.