Sounds similar to a HYCALM. That's "How Ya Call Em" according to my late Uncle John. The term could be applied to anything for which the name was on the tip of your tongue, but escaped your immediate recall. I remember him using the term often when I was a kid helping him around the farm. He would ask me to hand him a "hycalm" and I would hand him a wrench or whatever. Often it was the wrong wrench or tool. However, it is surprising how, with practice, one gets better at guessing what he was asking for.
I think the most commonly used equivalent term is "Whatchamacallit."