The Internet has been defined as a 'network of networks'. That is correct — telecommunications companies lay fiber throughout the world and trade Internet traffic over those connections. That traffic is made up of all the movies, photographs, and memes that you see on a daily basis. That is referred to as 'content'. The Internet's heart is located between this telecommunications component and the material that users send to one another over those cables. That is the 'infrastructure' of the Internet.
The physical hardware, transmission media, and software used to connect computers and people on the Internet are referred to as Internet infrastructure. The Internet infrastructure is in charge of hosting, storing, processing, and serving the data that comprises websites, apps, and content.