Sentence:  The spices used in this bread are "zaatar" and <WSD>"sumack</WSD>". [...] <WSD>"Sumack</WSD>" is a spice derived from the berries of a bush that grows wild in all Mediterranean areas. The berries are dried and crushed to form a coarse purple-red powder. It has a sour taste. 
Meaning of the word marked with <WSD> tags:  A sour spice popular in the Eastern Mediterranean, made from the berries of tanner's sumac.