Core Set 2021 introduced the keyword 'mill':
Mill N cards (Put the top N cards from the library into your/their graveyard.)
which was named after the card Millstone with the ability
{2}: Take the top two cards of target player's library and place them in target player's graveyard.
See e.g. this MTG Wiki article:
Ultimately, the term "mill" was chosen both in reference to the original card and because it was already so popular as an informal term—it has permeated into other games and some dictionaries, despite the oblique etymology.
Are there any other keywords which were named after one of the first cards on which they appeared?