One way to find out the name of a weird mathematical structure is to look at the source code of related Haskell libraries.
I just learned from Algebra.Lattice.Wide that adding a top and bottom element to a set to form a lattice
data Wide a = Top | Middle a | Bottom
is called the flat lattice. Which is not the name of this thing in the code, but at least the commit history had the sane name that I could look up elsewhere. Apparently, the corresponding abstract interpretation is the constant abstraction.
(Of course, such obscure names are useless and are just impressive-sounding word salad. Luckily, I’m forced to write some impressive-sounding word salad right now. )