Quiz: Remember the definition of mal de mer?
The most serious accident that can occur at a nuclear reactor. In a meltdown, the radioactive material in the reactor becomes very hot, melting some or all of the fuel in the reactor. A meltdown may or may not be followed by the release of radioactive material to the environment. A partial meltdown, with very little external radiation, occurred at Three Mile Island in 1979; a complete meltdown happened at Chernobyl in 1986.
Something very long and tedious told or explained exhaustively: I've been listening to all this here Megillah/Let's not have the megillah/a whole megilla (song and dance)
[1909+; fr Yiddish fr Hebrew, ''scroll, volume,'' esp the Book of Esther read aloud in its entirety at Purim celebrations]