If Arduino was an acronym where does it stand for

Given it was designed by Italians, if it were an acronym, I would imagine they would have used Italian words instead of English.

Sometimes the name is chosen, so it is not an acronym, such as the ISO (International Organization for Standardization) whose name is not a direct acronym in any of their official languages. Quoting from iso.org: Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, the short form of our name is always ISO.