The word manna carries within it what may be the oldest recorded expression of bewilderment. According to the Book of Exodus (16:15), when the Israelites found the mysterious substance on the ground in the wilderness, they asked mān hū — "What is it?" The Hebrew word mān, whether it derives from this question or from a separate root meaning portion or substance, became the name of the miraculous food.
The biblical account describes manna as appearing with the morning dew, white like coriander seed, tasting like wafers made with honey. It could be ground, boiled, or baked into cakes. It appeared six days a week but not on the Sabbath, when a double portion from the previous day sustained the people. For forty years, according to the narrative, manna fed the Israelites during their wilderness wandering.
Naturalistic explanations for manna have been proposed since antiquity. The most compelling identifies it with the honeydew secretion of scale insects (Trabutina mannipara) feeding on tamarisk trees in the Sinai Peninsula. These insects excrete a sweet, white, flaky substance that drops to the ground and hardens in the cool night air. Bedouin peoples still collect this substance, known in Arabic as mann. In Iran, a similar
Another candidate is the lichen Lecanora esculenta, which grows in thin crusts on rocks across the Middle East and Central Asia. Wind can detach fragments of this lichen and scatter them across the desert floor, creating the appearance of food falling from the sky. The lichen is edible, if not particularly palatable.
The word entered Greek as manna through the Septuagint translation of the Hebrew Bible, then passed into Latin, from which it spread to all European languages. In English, manna appears from the Old English period, testament to the centrality of biblical vocabulary in the earliest strata of English literacy.
The metaphorical extension of manna to mean any unexpected benefit or windfall is attested from the 14th century. The phrase "manna from heaven" has become a standard English idiom, applied to everything from financial windfalls to fortunate coincidences. The theological concept of unearned divine provision has been thoroughly secularized, but the sense of grateful amazement embedded in the original Hebrew question — what is this? — persists in the word's connotations.