If you're in the US, your debit card is likely a Visa or Mastercard debit card.
I'm in the UK, and every debit card I've ever had has been a Visa or Mastercard
For contrast, I'm Swiss, and all of my debit cards have either been Maestro or PostFinance (in Switzerland, the Postal Service runs a bank which maintains its own debit card scheme).
Maestro is technically a MasterCard debit card, but I'm not aware of a possibility to use it for online payments. VPay (i.e. "proper" VISA debit) is starting to make inroads.
That being said, YMMV.