whatsitsname means any object whose name one does not know or cannot remember or immediately bring to mind. Lexicurio rates it Sui generis — a strength score of 90 out of 100.
Etymology
From what's + its + name.
noun
- Any object whose name one does not know or cannot remember or immediately bring to mind.“Hey, hand me the whatitsname, will you? I need to tighten the doodah on this thingummybob.”