מַצָּה
matstsah (mats-tsaw') n-f.
1. (properly) sweetness
2. (concretely) sweet (i.e. not soured or bittered with yeast)
3. (specifically) an unfermented cake or loaf
4. (elliptically) the festival of Passover (because no leaven was then used)
[from H4711 in the sense of greedily devouring for sweetness]
KJV: unleaved (bread, cake), without leaven.
Root(s): H4711
H4711