Italian disastro describes being ill-starred. It reflects an astrological explanation of calamity: the heavens were unfavourably arranged. French désastre carried the word into English, where a disaster needs no celestial explanation.
English borrowed from both French and Italian. These cards reconstruct the route through French, not the only possible route.
Sources
- Merriam-Webster · disaster
Dictionary word history; the component and historical references below supply additional detail.
- Online Etymology Dictionary · disaster
Historical forms, meanings, and context for the route described here.