מצּה
matstsâh
mats-tsaw'
From H4711 in the sense of greedily devouring for sweetness; properly sweetness; concretely sweet (that is, not soured or bittered with yeast); specifically an unfermented cake or loaf, or (elliptically) the festival of Passover (because no leaven was then used)
KJV Usage: unleavened (bread, cake), without leaven.