Informal any device, contrivance, gadget, etc.: jocular substitute for a name not known or temporarily forgotten
Origin of thingamajigextension of older thingum, thing
Something whose name is unknown or forgotten.
Origin of thingamajigAlteration of obsolete thingum (from thing) + jig1.
- Something that one does not know the name of.
- He used this, this... this thingamajig you saw him with the other day to fix the problem.