Motsu and Horumon are the Same Things or Different?
As I wrote in this article, “Horumon (ホルモン)” is a Japanese word for “internal organs” referring to pork and beef offal, especially intestines.
Regarding the origin of the word, there are various theories, but the following two are well-known.
One says it is derived from “horumon (放る物: meaning discarded things)” in the Osaka dialect, while the other believes that it was named after “hormone” or “hormon”.
We often eat those variety meats in the Yakiniku grill and “Horumonyaki (ホルモン焼き)”, a Japanese grilled dish whose main ingredient is Horumon.
What is Motsu (もつ)?
In Japanese food culture, there is one more word for beef and pork (and chicken) innards, which is “Motsu (もつ)” whose origin comes from “zomotsu (臓物: meaning internal organs)”.
As with Horumon, Motsu, in a narrow sense, refers to intestines offal used in dishes such as the “Motsunabe (もつ鍋)” hot pot and the “Motsuyaki (もつ焼き)” grill.
As you can see from the above, Horumon and Motsu are basically the same things.
(Reference Pages: Wikipedia ホルモン焼, もつ, Macaroni )