A ticket type is a named entry option an attendee selects at registration, such as General Admission, VIP, Member or Exhibitor, each with its own price and access.
Price, what the holder can access, and often what they are asked at checkout. General Admission, VIP, Member, Speaker and Exhibitor are the common set. The access part is the one that matters operationally, because it decides which sessions, rooms and areas a badge opens.
A ticket type is what someone bought. An attendee type is the category they belong to, such as member or non-member, student or staff. They frequently line up, and they come apart the moment a sponsor is given a complimentary VIP ticket. Model them separately if your reporting needs to tell those two people apart.
Every additional ticket type is another decision at checkout, and checkout is where you lose people. If a buyer is scrolling a long list trying to work out which one applies to them, the list is too long. Use access rules and questions on the order form to handle variation rather than spawning a new type for every case.
Ticket types are set up with their own prices and restrictions, display logic controls which ones a given visitor sees rather than showing everyone everything, attendees can register for sessions at the point of buying a ticket, and an admin can move someone between types after purchase through a ticket exchange. See ticketing and registration.