Can we just use the term "duck-typed" already? There's a significant difference between weakly-typed C, strongly-typed rust, and "strongly"-typed JavaScript/Ruby. Besides, weak-typing is relative. Javascript does some type conversion, but because it does less than C, it is more strongly typed than C, but it is more weakly typed than some other languages.

No, duck typing is not a very good distinguishing characteristic anymore. "Interfaces", "traits", and "concepts", to say nothing of other things, all in various ways make static languages have something that looks something like statically-checked duck typing. Duck typing isn't unique to dynamic languages.