You can just Google any definition. Not sure if there’s anything special about new words though and no idea where the data is from.
I’m not super sure how it works, but all the ones I’ve seen are from books (mostly) or other external databases. I don’t know if regular users can import them or if it has to be staff. I know this has come up in the forum before so maybe look around a bit.
https://forum.inaturalist.org/t/please-add-to-inat-free-to-use-list-with-all-19386-official-dutch-species-names/13024
https://forum.inaturalist.org/t/create-a-system-for-importing-common-names/3513
I’m pretty sure this isn’t the case, but I could be wrong.