The Spanish word 'así' meaning 'thus' or 'so' comes directly from the Latin word 'sic', which had the same meaning. The Latin 'sic' evolved phonetically into 'así' in Spanish, with the addition of an initial 'a-' (a common phenomenon in Spanish evolution from Latin) and the softening of the final '-c' to '-í'.

While 'así' itself is a fairly basic Spanish word, it appears in many common Spanish phrases like 'así que' (so that), 'así como' (just as), and 'así es' (that's right). These combinations help expand the basic meaning of 'thus/so' into more specific contextual uses.

English speakers might recognize the Latin root 'sic' as it's still used in English, particularly in writing and academia. When you see '[sic]' in a quote or text, it means 'thus' or 'so' and indicates that something was quoted exactly as it appeared in the original, even if it appears incorrect. This is the same Latin word that gave Spanish 'así'.