What kind of plug has a round prong and a flat prong?

Question

I’m trying to find out which adapter I can get for this plug. It is for a small Christmas Angel.

Answer 1

It's commonly called a "loudspeaker plug" (or "speaker plug"). As there are other types of speaker plug, "speaker plug 2 pin" will get you plenty of results.

The one in your hand is male, the mating part might be called a female plug, or a socket.

They're fairly common for low voltage Christmas lights, but the actual voltage and whether AC or DC depends on the lights. I have successfully swapped power supplies between lights, but they were labelled

Answer 2

Believe it or not, it's one of those old DIN connectors that used to be common for low voltage devices like computer keyboards in the 1980s.

This one is not exactly what I'm used to because it's only a 2-pin style.

Check out DIN Connectors at Wikipedia and scroll all the way down to the "Other Designs" heading.