Kitniyot (Hebrew: קִטְנִיּוֹת, qitniyyot) is a Hebrew word meaning legumes. During the Passover holiday, the word kitniyot takes on a broader meaning to also include, in addition to legumes, grains and seeds such as rice, corn, sunflower seeds, sesame seeds, soybeans, peas, and lentils.
According to Orthodox Ashkenazi laws, Kitniyot may not be eaten during Passover by Jews. Although Reform and Conservative Ashkenazi Judaism currently allow for the consumption of Kitniyot during Passover, long-standing tradition in these and other communities is to abstain from their consumption.
The Torah (Exodus 13:3) only prohibits Jews from eating chametz during Passover. Chametz is leaven made from the "five grains": wheat, spelt, barley, shibbolet shu'al (two-rowed barley, according to Maimonides; oats according to Rashi) or rye. There are additional rabbinic prohibitions against eating these grains in any form other than matzo.
Among Orthodox Ashkenazi Jews, the custom (minhag) during Passover is to refrain from not only products of the five grains but also other grains and legumes. Traditions of what is considered kitniyot vary from community to community but generally include maize (North American corn), as well as rice, peas, lentils, and beans. Many also include other legumes, such as peanuts and soy, in this prohibition. The Chayei Adam considers potatoes not to be kitniyot because they were unknown in the time when the prohibition was created, an opinion followed today by nearly all Ashkenazi authorities.