Sumac is a spice made from the dried and ground berries of the sumac shrub, primarily from the species Rhus coriaria. It is commonly used in Middle Eastern and Mediterranean cuisines. The spice has a vibrant reddish-purple color and a distinctive tangy, lemony flavor with subtle fruity and slightly astringent notes. Sumac adds a bright, citrus-like acidity to dishes without the harshness of lemon or vinegar. Beyond its culinary uses, sumac has traditional applications as a dye and herbal remedy. It originates from subtropical and temperate regions and holds cultural significance, especially in Persian cuisine. Sumac is often used as a seasoning for meats, salads, vegetables, rice, and in spice blends like za'atar. It can also be used in marinades and dressings. Traditionally, it was used in Ancient Greek and Roman cooking as a citrus substitute before lemons became common in Europe. Sumac should not be confused with poison sumac, which is a different plant and can cause allergic reactions. In summary:

• Sumac is a reddish spice from dried sumac berries.
• It has a tangy, citrusy flavor often compared to lemon but milder.
• Used widely in Middle Eastern and Mediterranean dishes.
• Comes from the sumac shrub in the genus Rhus.
• Also used historically for medicine and dye.

This spice adds a distinctive sour and bright flavor to many dishes and is prized for its unique taste and color. If you want, I can also provide some examples of dishes or recipes that use sumac.