The gunslinger Roland Deschain describes ka-tet as being "one from many." Susannah Holmes derives an even simpler definition of the term: it is the notion of family. A tet often consists of several central individuals bound for a purpose, with additional individuals playing transitory roles and specific functions within the group.
One of the most famous ka-tets is that of Deschain, Holmes, Eddie Dean, Jake Chambers, and Oy of Mid-world; to a lesser degree, Donald Callahan, Ted Brautigan, Dinky Earnshaw, and Patrick Danville contributed to the purpose of this group. Deschain formerly belonged to another long-ago tet that included Cuthbert Allgood, Alain Johns, and (for a time) Sheemie Ruiz and Susan Delgado.
Groups that might be considered ka-tets which were never specifically identified as such include:
- It: Bill Denbrough, Mike Hanlon, Ben Hanscom, Richie Tozier, Stan Uris, Eddie Kaspbrak, and Beverly Marsh
- The Stand: Stu Redman, Larry Underwood, Glen Bateman, and Ralph Brentner
- Dreamcatcher: Gary Jones, Henry Devlin, Joe Clarendon, and Pete Moore
- Cell: Clayton Riddell, Tom McCourt, Alice Maxwell, Ray Huizenga, Daniel Hartwick, and Denise Link
- Under the Dome: Dale Barbara, Julia Shumway, Rose Twitchell, Rusty Everett, and Joe McClatchey
The concept is similar to Kurt Vonnegut's notion of karass, which is generally "a group of people who, often unknowingly, are working together to do God's will. The people can be thought of as like the fingers that support a cat's cradle."
By extension, Vonnegut's concept of duprass – described as "a karass that consists of only two people...[who]...live lives that revolve around each other" – may be, in reverse, applied to such couples as Lisa Debusher and Scott Landon, and Johanna Arlen and Mike Noonan.