There's no such distinction. But, in the operational semantics of a call-by-value language, variables are only substituted with values. Or, to be consistent wi

There's no such distinction. But, in the operational semantics of a call-by-value language, variables are only substituted with values. Or, to be consistent with the terminology I've used in other comments, in any language, a value is something a variable can be substituted with. It's just that, in a call-by-value language, variables can never be substituted with unfinished computations.