OTT refers to the service being delivered via L3 IP, hence the ISP/Telcom can't block it or charge for it (as they would prefer to in the intests of making more money). So the content is flying "over the top" of their gate.
(Telcos didn't want the internet to exist, with its service neutral model : they wanted to sell "value added" services over their wires).
(Telcos didn't want the internet to exist, with its service neutral model : they wanted to sell "value added" services over their wires).