I think that's usually how it breaks down in practice but even if the language directly provided format strings, I'd still call them format strings, and even if

I think that's usually how it breaks down in practice but even if the language directly provided format strings, I'd still call them format strings, and even if a library provided string interpolation, I'd call it string interpolation. The difference is format strings are a string with indicators that say where to insert values, usually passed as additional arguments, which follow after the string. String interpolation has the arguments inside the string, which says how to pull the values out of the surrounding context.