According to the Wiki, an over-the-top (OTT) media service (also known as a streaming platform) is a media service offered directly to viewers via the Internet. OTT bypasses cable, broadcast, and satellite television platforms - the mediums through which companies have traditionally acted as controllers or distributors of such content.

It has also been used to describe no-carrier cellphones, for which all communications are charged as data, avoiding monopolistic competition, or apps for phones that transmit data in this manner, including both those that replace other call methods and those that update software.

The term is most synonymous with subscription-based video on demand (SVoD) services that offer access to film and television content. Such content may include shows and movies for which the OTT acquired rights have from the content owner. Programming may also (or alternatively) include original content produced specifically for the service.

OTT services also include a range of "skinny" television offerings that provide access to live streams of linear specialty channels. These services resemble traditional satellite or cable TV programming, but the OTT content is delivered via the public Internet instead of a closed, private network systems that exclusive equipment like set-top boxes.

OTT services are typically accessed via websites on personal computers, apps on mobile devices (such as smartphones and tablets), digital media players (including video game consoles) or televisions with integrated Smart TV platforms.

Reference: adtagmacros.com