'assalto' originates from Italian, ultimately from Late Latin 'assaltus' or 'assaltare' (see also Medieval Latin 'assultare'), where the prefix 'ad-' (later assimilated to 'as-') meant 'to, toward' and 'saltare/saltus' related to 'leap' or 'jump'.

'assaltare' (Late Latin/Medieval Latin) passed into Old Italian as 'assaltare/assalto' and became the modern Italian noun 'assalto'; it is cognate with French 'assaut' and English 'assault' which entered English via Old French.

Initially it carried the sense of 'a leaping on' or 'a sudden attack' (literally a 'leap/charge onto'), and over time it retained that core idea, broadening to include 'robbery' or 'hold-up' in some contexts.