Terminology: words with only terminals vs. words which can contain nonterminals
A standard term would indeed be sentential form. I think it can be used on its own, not only bound to a grammar.

It makes more sense when you know that words are also called sentences, probably harking back to the beginnings of formal grammars in the study of natural languages.

That said, there is precedence for pattern in the study of pattern languages. While they work nothing like grammars, mixed strings of alphabet symbols and variables have this name there.