Shmuel said that the phrase: “The bread of affliction [leḥem oni]” (Deuteronomy 16:3) means bread over which one answers [onim] matters, i.e., one recites the Haggadah over matza. That was also taught in a baraita: Leḥem oni is bread over which one answers many matters. Alternatively, in the verse, “leḥem oni” is actually written without a vav, which means a poor person. Just as it is the manner of a poor person to eat a piece of bread, for lack of a whole loaf,

haggadah Section: Maggid - Beginning