Payment service provider Vs payment Gateway

I found a Payoneer blog that talks about the differences between providers, gateways and others. You can check it out here.

To answer your question:

• Payoneer in this case would be considered a payment service provider.

• The type of integration Payoneer (payment service provider) is different than 2Checkout (Payment Gateway). 2Checkout is a partner of Payoneer, and the integration set up between the two is to allow the transfer of funds between your 2Checkout account to your Payoneer account.
  A gateway provider integration is done directly with the website which provides you with a plugin that will allow visitors to pay you directly.

• Depending on the mass payout company that works with Payoneer, different fees may apply for loading the funds. No two fees are ever the same when it comes to partnering companies. This information is normally available on the payout company's page when choosing a payment preference.
  If your a new Payoneer user and you created the account through 2Checkout's website, the fees that apply will also appear in your Payoneer account under the card fees section.