ATO noun6 •Initialism of account take over.Interestingly, the nature of the available stolen data means the typical victim of an ATO attack varies slightly depending on whether a bank or a retailer is under attack. — 2022 •Acronym of anti-terrorist operation. •Initialism of automatic train operation. •Acronym of ammunition technical officer. •Acronym of abort to orbit. •Acronym of assisted take-off. formsATOs