From matsats in the sense of greedily devouring for sweetness; properly, sweetness; concretely, sweet (i.e. Not soured or bittered with yeast); specifically, an unfermented cake or loaf, or (elliptically) the festival of Passover (because no leaven was then used) -- unleaved (bread, cake), without leaven.
see HEBREW matsats
H4682. matstsah
I. מַצָּה noun feminine unleavened bread, or cake(s); — absolute ׳מ Leviticus 2:5; 8:26 (מ ׳חַלַּת אַחַת), Numbers 6:19 (id.), 6:19; usually plural מַצּוֺת Exodus 12:15 44t.; מַצֹּת 12:18 3t; — unleavened bread, prepared in form of לֶחֶם 29:2; חַלָּה 29:2 4t. P; רקיקים 29:2; 1 Chronicles 23:29 4t. P; עגּה Exodus 12:39; used at ordinary meals (prepared hastily): מ ׳אפה Genesis 19:3 (J), Exodus 12:39 (J), 1 Samuel 28:24; probably also Judges 6:19-20, 21 (twice in verse); elsewhere at sacrificial meals, e.g. ritual peace-offerings Leviticus 2:4 (twice in verse); 2:5; 6:9; 7:12 (twice in verse); 10:12; consecration of priesthood Exodus 29:2 (3 t. in verse); 29:23; Leviticus 8:2, 26, 26; at peace-offering of Nazirite Numbers 6:15 (twice in verse); 6:17, 19 (twice in verse); at Passover Exodus 12:8; Numbers 9:11 (all P); especially at feast of unleavened bread [cakes] for 7 days after Passover המ חג ׳שׁמר Exodus 23:15 (E), 34:18 (J); מ ׳שׁסר 12:17 (P), (ה)מ ׳חג עשׂה2 Chronicles 30:13, 21; 35:17; Ezra 6:22; המ ׳בחג Deuteronomy 16:16; 2 Chronicles 8:13; המ ׳חג ׳לי Leviticus 23:6. During these seven days all Israel ate מצות Exodus 12:15, 18, 20 (P), 23:15 (E), 13:6-7, 34:18 (J), Leviticus 23:6; Numbers 28:17 (P), Deuteronomy 16:3, 8; Joshua 5:11; Ezekiel 45:21. — 2 Kings 23:9 read probably מִצְוֺת or מִנָיוֺת for ׳מ ᵑ0 (אכל); so Gei Kue Kmp Bu.
[מָצֻק] see מָצוּק below II. צוק
[מְצֻקָה] see מצוּקָה below I. צוק
[מֻצֶ֫קֶת] see ׳מוּצ below יצק. מֵצַר see I. צרר.
מצר (√ of following)