Similar words
sanitário
Worth distinguishing: sanitário is just the toilet/restroom itself; banheiro is the whole bathroom.
Similar in other languages
German
Badezimmer
Badezimmer is the German word for the same thing — both mean "bathroom."
French
salle-de-bain
salle-de-bain is the French word for the same thing — both mean "bathroom."
Practice
1 What does banheiro mean?
bathroom
2 Fill the gap: Onde fica o ___?
Full sentence: Onde fica o banheiro? (Where is the bathroom?)
3 Which fingerprint chart matches banheiro?
banheiro: neutral register, core frequency, general domain, neutral connotation.