Ticket Master
In short
Ticketmaster is a global company that sells tickets for live music, sports, and theatre events. It operates as a subsidiary of Live Nation Entertainment.
In plain words
It is a massive online shop for event tickets. When you want to see a concert or a football match, you often use this website to buy your seats.
A simple example
A fan visits the Ticketmaster website to purchase a digital ticket for a Taylor Swift concert. They pay online and receive a barcode on their phone to enter the stadium.
Why it matters
It controls a huge part of the live entertainment market. Because it works with so many venues and artists, it has significant influence over ticket prices and availability.
Easy to mix up
Do not confuse it with a secondary resale site like Viagogo, although Ticketmaster does have a resale platform.