「おにぎり」は白米を三角形や俵形に握り固めた食べ物で、真ん中にいろいろな具を入れたり、海苔を巻いたりして食べます。「おにぎり」の歴史は非常に古く、弥生時代中期から後期の杉谷チャノバタケ遺跡（石川県）では粽状の炭化米が発見され、これが日本最古のおにぎりと言われています。また平安時代には御強（おこわ）を卵状に丸く固めた「屯食（とんじき）」が配られたと記録が残っており、これが「おにぎり」の原型とされています。一方、「おむすび」という言い方もあります。この両者の違いを説明することは難問です。一説によれば「おむすび」という言葉は、天地万物を生み出す神霊やその霊妙な力を意味する「むすび」から来ており、我々の先祖は山を神格化し、神の力に肖ろうと米を山型（三角形）に象って食べた･･･それが「おむすび」の始まりとされます。従って三角形のものが「おむすび」、形状は問わず握り固めたものが「おにぎり」です。
Onigiri known as a rice ball in English is a chunk of rice shaped in various shapes (usually triangle or sphere) with different ingredients inside. Sometimes you wrap seaweed around it. The history of Onigiri is very long starting from the middle of Yayoi period. In Sugitani-Chanobatake ruin (Ishikawa pref.), a carbonized rice shaped something like a rice ball was discovered and it is said that it’s the oldest Onigiri in Japan. Also there is a record saying that in Heian period something called “Ton-ziki” which is an Okowa rice ball (Okowa is steamed Mochi-rice) was given out. This is thought to be the model of Onigiri. On the other hand, Onigiri is caleed Omusubi. It is very difficult to explain the difference but it is said that Omusubi derived from the word “Musubi” which means connection in Japansse. It is also said to have the power to create “the whole creation” and its miraculous powers. In ancient times, our ancestors deificated the mountains and tried to shape their rice in a triangle to make it look similar. This is also said to be the beginning of Omusubi. Therefore, it is natural to think a triangle shaped rice ball is Omusubi and other shaped rice balls are Onigiri, but ther is no set rules how to call them.