whatchamacallum
/ˈwʌtʃəməˌkɔləm/
noun
- A variant of 'whatchamacallit'; used when you cannot remember or do not know the name of something.
- The mechanic used a whatchamacallum to adjust the engine.
- He asked for a whatchamacallum to open the package.
- I can't find the whatchamacallum for the vacuum cleaner.