The Spanish word 'raro' meaning 'rare' or 'strange' comes directly from the Latin word 'rarus', which meant 'sparse', 'rare', or 'exceptional'. The meaning has remained remarkably stable over time, with only a slight extension to include the sense of 'strange' or 'odd' in Spanish, which is a natural semantic development since things that are rare or uncommon are often perceived as strange.

While 'raro' itself is a relatively common and simple Spanish word, you might encounter it in phrases like 'rara vez' meaning 'rarely' or 'seldom'. The feminine form 'rara' is used in exactly the same way to describe feminine nouns.

English speakers can easily remember 'raro' by connecting it to the English word 'rare', which comes from the same Latin root 'rarus'. Just as 'rare' in English can mean both 'uncommon' and 'exceptional', 'raro' in Spanish carries similar meanings plus the additional sense of 'strange'. Another English cognate is 'rarity', showing the same etymological connection.