You do wonder how it got the name, don’t you? It’s the 11th month in the French Revolutionary calendar. From the Greek, Thermos. Now, you may say “it’s not very hot in November,” and you’d be right. They rejiggered the entire calendar so the 11th month was in the summer.

Name origin theories are split:

The food Lobster Thermidor was named, directly or indirectly, after the month. (Sometimes it is said that it was first prepared for Napoleon I during the month of Thermidor; others[who?] say that it was created by Tony Girod at the Café de Paris to celebrate the opening of a play called Thermidor.)

Who indeed. The Wikipedia entry on the play is quite certain the dish was named after the theatrical work.

Anyway, looks like barf.