plural of dungeon master

(role-playing games) A person conducting a role-playing game, generally responsible for controlling all beings and processes other than the players, either individually or as part of a team.

(role-playing games) A game master in Dungeons & Dragons games.

(zoology) carrier shell (family Xenophoridae)

plural of Master of the Universe

(religion) God / (idiomatic) A powerful person. / (idiomatic, finance, business) A highly successful business person.

plural of coronal mass ejection

(astronomy) A massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space.

Used other than figuratively or idiomatically: see mass, destruction. / (uncountable, idiomatic) Killing of large numbers of people.

mastoid process.