thumbnut
/ˈθʌmˌnʌt/
noun
- A nut (metal fastener) with ridges or wings that allow it to be turned by hand without a tool.
- She spun the thumbnut off the threaded rod in seconds.
- I tightened the thumbnut on the lamp base with my fingers.
- The mechanic replaced the bolt with a thumbnut for easier adjustments.
Synonyms