From their about page, it's 'Surinamese for “Start over again”'. It seems to be pronounced as "Ah-dee-yen".
To me it sounded very much like Limburgs dialect (specifically Kerkraads dialect) "adieë wa" (only first part, but sometimes the second part is omitted anyway) [1]
English Wikipedia also has an entry for the company Adyen, btw [2].