I,ve seen one of those before but can,t remember where.Perhaps a carving fork,to hold the bird or roast while you carve it with the carving knife?A guess mind you.
Olive fork or pickle fork, but if you google pickle fork it will also show you a car tool for removing ball joints, so google olive fork or condiment fork. Hard to say if it is older as some modern ones have an antique styling to them, are there any hallmarks on it or does it say stainless or something?
I have seen exactly that but with a matching associated knife. The books called it a meat carving tools. The little small forks like that was used to retrieve food portions out of gravy or maybe a large pickle out of a jar. more here: https://duckduckgo.com/?q=two+pronged+fork&t=h_&iax=images&ia=images
I have one very similar, it is an Italian olive fork. They're usually made of either .800 silver or Nickle Silver (an alloy of copper and nickle), it looks to be the Nickle Silver version as the tarnish is similar to what that would be and without hallmarks I would bet with 95% certainty that's what it is.