The library's Discovery Catalog Search searches more than just TCC library's holdings. It searches through a lot of TCC's databases all at once, as well as other library systems for items we can borrow from those institutions in a process called "interlibrary loan" or, "ILL."
If the item is something TCC owns, it will say "Held by Tulsa Community College Library" and will tell you the location (campus and collection), plus the call number. It will allow you to place a hold on the item via the blue button, as seen here:
If the item is not something the TCC library owns, it will present you with an option to ILL, which is a free service to you. You can learn more about ILL via the links below. The ILL button will look like this (under the "Check Availability" bar):