Onigiri vs Omusubi (Musubi) vs Nigirimeshi
When a Japanese mother prepares a Bento boxed lunch that her kid eats at school, she often makes rice balls, together with various side dishes.
The rice packed together in a ball is generally called “Onigiri (おにぎり)“, which comes in many varieties. It’s comfort food in Japan, where groceries and convenience stores carry it.
As you may already know, Onigiri has another name of “Omusubi (おむすび)” or “Musubi (むすび)” or “Nigirimeshi (にぎりめし)”.
But are there any differences between these? Today, I did online research about that.
Onigiri vs. Omusubi vs. Nigirimeshi
When we Japanese mention the dish in daily life, we often use the word Onigiri or O-Musubi. Whether using which depends on the person.
It is generally said that Onigiri is the word commonly used in the western part of Japan, while Omusubi tends to be often used in Eastern Japan.
But in reality, over 80 percent of people are using the word Onigiri in everyday conversation.
Shape
In general, no matter what shape is okay concerning Onigiri.
Historically, the word was derived from Nigirimeshi. So they both can have any shape, typically covered with a sheet of nori seaweed.
On the other hand, in many cases, Omusubi refers to a rice ball with a triangle shape that is covered partly with a dry sheet of nori.
Meaning
In terms of meaning, based on this article on Onigiri Japan and Kojien, one of the most authoritative dictionaries of the Japanese language;
Onigiri, Omusubi, and Nigirimeshi refer to the same thing.
(Reference Page: Wikipedia おにぎり )