Similar words
somente
só is more colloquial and short; somente is more formal or written — both mean "only."
Similar in other languages
French
seulement
seulement is the French word for the same thing — both mean "only."
Practice
1 What does só mean?
only
2 Fill the gap: ___ quero dormir.
Full sentence: Só quero dormir. (I only want to sleep.)
3 Which fingerprint chart matches só?
só: neutral register, core frequency, general domain, neutral connotation.