It's tough to say what "idea" means. Take the "cap" from John Christopher's Tripods books. The aliens used it to keep adult humans docile. It is placed on them

It's tough to say what "idea" means. Take the "cap" from John Christopher's Tripods books. The aliens used it to keep adult humans docile. It is placed on them during puberty. That is not in here as "cap". But is it some other thing? Perhaps "Remote-Control Slavery Mental control (possibly mediated by radio waves) of individuals of other species."? And it uses terms as synecdoche, like how 'Bergenholm Drive' is 'A device that renders a spaceship free of inertia', rather than the more general category of 'inertialess drives', which is also used in Warhammer 4k (https://warhammer40k.fandom.com/wiki/Inertialess_Drive https://warhammer40k.fandom.com/wiki/Inertialess_Drive ), Theodore Sturgeon's "Sturgeon" (https://archive.org/details/galaxymagazine-1956-08/page/n131/mode/2up?q=%22inertialess%22 https://archive.org/details/galaxymagazine-1956-08/page/n131...), and others (https://dbpedia.org/page/Inertialess_drive https://dbpedia.org/page/Inertialess_drive). Those interested in this list may like the Historical Dictionary of Science Fiction at https://sfdictionary.com/ https://sfdictionary.com/ and The Oxford Dictionary of Science Fiction (https://archive.org/details/bravenewwordsoxf00pruc/ https://archive.org/details/bravenewwordsoxf00pruc/).