From Latin *subridēre* ("to smile beneath"), a compound of *sub-* ("under, slightly") + *ridēre* ("to laugh"). The prefix *sub-* conveyed a softer, gentler action than full laughter — giving us a word that has always meant a smile rather than a laugh. The related noun *sorriso* (smile) follows the same root.

In Brazil, smiling at strangers in public is generally seen as warm and friendly, reflecting the country's famously sociable culture. In Portugal, smiles between strangers tend to be more reserved — offering a big smile to someone you don't know might even seem unusual. Don't confuse *sorrir* (to smile) with *rir* (to laugh); they share a root but are distinct actions in both meaning and register.