Full Idea
We can talk of a 'zero-place' function, which is a new-fangled name for a familiar item; it just has a single value, and so it has the same role as a name.
Gist of Idea
A 'zero-place' function just has a single value, so it is a name
Source
David Bostock (Intermediate Logic [1997], 8.2)
Book Reference
Bostock,David: 'Intermediate Logic' [OUP 1997], p.334