mid-13c., ris, "edible seeds or grains of the rice plant, one of the world's major food grains," from Old French ris, from Italian riso, from Latin oriza, from Greek oryza "rice," via an Indo-Iranian language (compare Pashto vriže, Old Persian brizi), ultimately from Sanskrit vrihi-s "rice."
The Greek word, directly or in indirectly, is the source of the European words for the grain (Welsh reis, German reis, Lithuanian ryžiai, Serbo-Croatian riza, Polish ryż, etc.). Evidence of semi-cultivated rice in Thailand dates to 5,500 years ago; introduced to the Mediterranean by the Arabs, it was introduced 1647 in the Carolinas.
Rice paper (1810), originally used in China, Japan, etc., is made from straw of rice; the name is sometimes misapplied to a delicate white film prepared from the pith of a certain East Asian shrub. Rice-pudding is by 1889. Rice Krispies is from 1936.