salvoyoudaoicibaDictYouDict[salvo 词源字典]
salvo: [16] When English originally acquired the word salvo, it was in the forms salve or salva, which came respectively from French salve and its source, Italian salva. This originally meant ‘salute, greeting’ (it came from salvē ‘hail’, the imperative form of Latin salvēre ‘be in good health’, which is related to English safe, salubrious, salute, save, etc).

Important personages being greeted with a volley of gunfire, salva soon came to be used for such a discharge of guns (the related English salute has developed along the same lines – as in a ‘21-gun salute’). The form salvo, which emerged in the 17th century, is an alteration of salva.

=> safe, salute, save[salvo etymology, salvo origin, 英语词源]
salvo (n.)youdaoicibaDictYouDict
1719, alteration of salva (1590s) "simultaneous discharge of guns," from Italian salva "salute, volley" (French salve, 16c., is from Italian), from Latin salve "hail!," literally "be in good health!," the usual Roman greeting, regarded as imperative of salvere "to be in good health," but properly vocative of salvus "healthy" (see safe (adj.)). The notion is of important visitors greeted with a volley of gunfire into the air; applied afterward to any concentrated fire from guns.