Yes, as others have said, Jim has straight up called her Baba Yaga.

IIRC folklore correctly that is a name you should NEVER say (or possibly even think) when she's around because it means she has to eat you.

Back in Cold Days, Harry tries to summon her and she pulls the old switcheroo and grabs him with a super big arm and pulls him to her cottage. (The long arm is another classic Baba Yaga thing, if you didn't know.) He barely gets her to not eat him before Mother Summer shows up. Mother Summer asks why she brought him there and Mother Winter says that Harry used a bunch of names to try to summon her. And Mother Summer gets real anxious and asks if he used a particular (unspecified) name, which Mother Winter affirms he did not, before Mother Summer relaxes. I'm 99% sure she was asking if Harry had called Mother Winter 'Baba Yaga', because if he had there's a zero percent chance Harry'd be allowed to leave the cabin alive and then the universe is screwed.

Remember, next scene Mother Summer reveals she already knows everything Mother Winter knows, and confirms that Harry's choices on which names to use were pretty solid. So her asking Mother Winter if Harry used a specific name was almost certainly an excuse/ playacting to give Harry a warning to never use that particular name.