[michaelochurch]

They're very similar. I would say the only difference is that I intend on using function for a specific subset of nonsymbols, and also that I intend for it to be a code construct (nonsymbols are not code; in fact, it's impossible to capture most nonsymbols in code). Pathological nonsymbols do not really feel like functions. However, one could construe nonsymbols as being HOFs (the worst of which would be ill-typed in any sane type system, such as Haskell's).