Literally translated, buongiorno pianoforte ( also written as two words: buon giorno) means good day. good afternoon ( very early afternoon) synonym: buon pomeriggio. buon giorno definition: good day ; hello | meaning, pdf pronunciation, translations and examples in american english buongiorno vita spartito pianoforte pdf ( spartito by extension) hello. buon is the italian word for good, and giorno is vita the italian word for day. typically, italians use buongiorno as a greeting until about 5 or 6pm, after which they switch to buonasera! hyponyms: ( during daytime) buondì, ( during nighttime) buona notte.