Za'atar (Arabic: زَعْتَر‎ za‘tar, also romanized zaatar, za'tar, zatar, zatr, zattr, zahatar, zaktar or satar) is a generic name for a family of related Middle Eastern herbs from the genera Origanum (Oregano), Calamintha (Basil thyme), Thymus (typically Thymus vulgaris, i.e., Thyme), and Satureja (Savory). The name za'atar alone most properly applies to Origanum syriacum. It is also the name for a condiment made from the dried herb(s), mixed with sesame seeds, dried sumac, and often salt, as well as other spices. Used in Arab cuisine, both the herb and spice mixture are popular throughout the Middle East.

Written history lacks an early definitive reference to za'atar as a spice mixture, though unidentified terms in the Yale Babylonian Collection may be references to spice blends. According to Ignace J. Gelb, an Akkadian language word that can be read sarsar may refer to a spice plant. This word could be attested in the Syriac satre, and Arabic za'atar (or sa'tar), possibly the source of Latin Satureia. Satureia (Satureja) is a common name for satureia thymbra, a species of savory whose other common and ethnic names include, "Persian za'atar", "za'atar rumi" (Roman hyssop), and "za'atar franji" (European hyssop).

Atar (Avestan ātar) is the Zoroastrian concept of holy fire, sometimes described in abstract terms as "burning and unburning fire" or "visible and invisible fire" (Mirza, 1987:389).

In the Avestan language, atar is an attribute of sources of heat and light, an adjectival form of nominative singular atarsh (ātarš). It is cognate with the athar- found in the name of the Atharvan, a type of Vedic priest, and with Serbian ватра / vatra (fire), which sets Serbian apart from other Slavonic languages, e.g. Russian (огонь = "fire"; Serbian also has огањ - "fire", but it is mostly poetic) but, according to at least one author, the ultimate etymology of atar is unknown (Boyce, 2002:1). The yazata Atar is not of Indo-Iranian origin (Dhalla 1938:174).^{[dubious – discuss]}

In later Zoroastrianism, atar (in middle Persian: ādar or ādur) is iconographically conflated with fire itself, which in middle Persian is ataksh, one of the primary objects of Zoroastrian symbolism.

Atar is already evident in the Gathas, the oldest texts of the compendium of the Avesta and believed to have been composed by Zoroaster himself. At this juncture, as in the Yasna Haptanghaiti (the seven-chapter Yasna that structurally interrupts the Gathas and is linguistically as old as the Gathas themselves), atar is still—with only one exception—an abstract concept simply an instrument, a medium, of the Creator and is not yet the divinity (yazata) of heat and light that atar was to become in the later texts.