It is worth noting that Yom Kippur is the only other day besides the weekly Sabbath, which is also referred to as a Sabbath. The weekly Sabbath is referred to as YHWH's Sabbath ["Today is a Sabbath of YHWH" (Ex 16,25); "Keep My Sabbaths" (Lev 19,3)] while Yom Kippur is referred to as Israel's Sabbath ["It shall be a Sabbath of restfulness for you" (Lev 16,31; 23,32)]. The Sabbatical Year (Shemitah) is also called the Sabbath of YHWH (Lev 24,4-5). It is also worth noting the term Shabbaton, which is used to describe some of the Holy Days. It should be emphasized that the term Shabbaton is not the exact equivalent of Sabbath [Shabbat] nor is it ever used interchangeably with it. Indeed, the term Shabbaton is derived from the same root as Sabbath although its exact connotation is unclear. Shabbaton seems to be the adjective form of the word Sabbath and means something like "Restfulness" or "rest-period". Thus the weekly Sabbath is described as a Shabbat Shabbaton, meaning a "Sabbath of Restfulness". Similarly, the 7th year is called a Shenat Shabbaton, meaning a "Year of Restfulness" (usually translated "Sabbatical Year"). The term Shabbaton is also applied to Yom Teruah (Lev 23,24), the first day of Sukkot (Lev 23,39), and Shemini Atseret (8th Day of Sukkot) (Lev 23,39).
The terms Sabbath and Shabbaton are never used to describe any of the days of Hag HaMatzot nor are ANY of the Holy Days ever called a Sabbath other than the weekly Sabbath itself. The only exception is Yom Kippur which is the holiest day of the year on which even eating is forbidden. In contrast, on the Holy Days of Hag HaMatzot (1st and 7th days) it is permissible to cook and have fire (Exodus 12,16).