People may have a gizmo or two in their washing machines, several thingamajigs in a car, and a few gadgets or a widget in a dishwasher. It wouldn’t be surprising if the appliances in a home also contained some thingies and thingamabobs. They’re all nondescript terms for mechanical parts or freestanding mechanical items.
The use of the word "gizmo," which can also be spelled gismo, is recent. During World War II, the US Navy began using the term, and sailors returning from the war quickly turned the word into common usage. Recorded writings that include the word don’t appear until the mid-1940s and early '50s.
Essentially, the term was used to describe a working mechanical part. Since mechanized equipment contained so many parts, the name might escape a person for a moment, who could say “Well it looks like that gizmo isn’t working properly.” It’s almost a fill word for lapse in memory, though soon the word simply applied to any running mechanical piece.
World War II was also a time when pilots, soldiers, and sailors might have lightly referred to mechanical failures as caused by gremlins. In cartoons of this era, gremlins were often depicted as removing a part or two from various moving vehicles. In tribute to the concept, Steven Spielberg created the film Gremlins, featuring a creature called a mogwai, named Gizmo, who was actually quite sweet unless you got him wet or fed him after midnight.
A gizmo can also be an object that doesn’t work in coordination with other parts. It may be an inventive or clever toy or a small feat of engineering. Technically, the term could be used to describe a cell phone, a mini remote control race car, an electronic bubble blower, or another similar device. In fact, virtually all infomercial electronic devices would fall under this heading.
The term can also be used to suggest that something is kind of neat or fascinating. It applies to a huge range of products, and just about anything battery or solar powered and handheld could be a gizmo. Of course, such devices could also be called thingies, gadgets, or another word. What term a person uses depends on which one the mind hits upon first. More often, the gizmo is the nondescript working part of machinery that the speaker doesn't understand, and while many individuals may not understand these parts, the world is full of them.