The word “onigiri” (OH-knee-GEEH-reeh) just became part of the Oxford English Dictionary this year. The humble sticky-rice ball — a mainstay of Japanese food — has entered the global lexicon. Key to onigiri is the stickiness of the rice. The rice balls are stuffed with a variety of fillings. Traditional favorites include salted plum or hot, spicy roe. The ball is then typically wrapped in seaweed. One Japanese proponent of onigiri calls it fast food, slow food and soul food. And mobile too. Early versions of onigiri are believed to have been consumed as far back as the times of “The Tale of Genji” in the 11th century.