Key
Key adjective - Coming before all others in importance.
Usage example: maintains that Sir Isaac Newton remains the key figure in physical science
Master is a synonym for key in principal topic. In some cases you can use "Master" instead the word "Key" as an adjective or a noun, when it comes to topics like main, fundamental.
Master
Master adjective - Coming before all others in importance.
Usage example: thought of themselves as belonging to humanity's master race
Key is a synonym for master in principal topic. Sometimes you can use "Key" instead the word "Master" as an adjective or a noun, if it concerns topics such as main, fundamental.
Mutual synonyms
How words are described
Both words in one sentence
- This allowed recovery of accounts in case of losing your master decoder key, but had an outrageous problem: You could no long sync passwords with a master password set on your Firefox user, requiring the user to disable it and then check-off passwords in the sync list.
Source: Darth Wiki / Idiot Programming - The 3rd Edition Dungeon Master's Guide mentioned a note played upon a lute as a possible key to open a magical door.
Source: Songs in the Key of Lock - In this case, the master console is enabled either by a command-line option or a special key, such as the tilde "~" on US keyboards or "`" on European keyboards (They're in the same position).
Source: Master Console
Cite this Source
Master and Key. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/key/master
Key & Master. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/key/master>.
Master or Key. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/key/master.
Google Ngram Viewer shows how "key" and "master" have occurred on timeline