"compacy, ropy lava," 1859, from Hawaiian, literally "smooth, polished."
"powdery remains of fire," Old English æsce "ash," from Proto-Germanic *askon (source also of Old Norse and Swedish aska, Old High German asca, German asche, Middle Dutch asche, Gothic azgo "ashes"), from PIE root *as- "to burn, glow." Spanish and Portuguese ascua "red-hot coal" are Germanic loan-words.
An ancient symbol of grief or repentance; hence Ash Wednesday (c. 1300), from custom introduced by Pope Gregory the Great of sprinkling ashes on the heads of penitents on the first day of Lent. Ashes meaning "mortal remains of a person" is late 13c., in reference to the ancient custom of cremation. Meaning "Finely pulverized lava thrown from a volcano" is from 1660s.
"act of washing, a cleansing," 1620s, from Latin lavationem (nominative lavatio) "a bathing, bath, bathing apparatus," noun of action from past-participle stem of lavare "to wash" (from PIE root *leue- "to wash"). Related: Lavations.
"a savoury dish of Italian origin, consisting of a base of dough, spread with a selection of such ingredients as olives, tomatoes, cheese, anchovies, etc., and baked in a very hot oven" [OED], 1931, from Italian pizza, originally "cake, tart, pie," a name of uncertain origin. The 1907 "Vocabolario Etimologico della Lingua Italiana" reports it is said to be from dialectal pinza "clamp" (from Latin pinsere "to pound, stamp"). Klein suggests a connection with Medieval Greek pitta "cake, pie" (see pita). Watkins says it is (perhaps via Langobardic) from a Germanic source akin to Old High German bizzo, pizzo "bite, morsel," from Proto-Germanic *biton- (see bit (n.1)). Ayto ["Diner's Dictionary"] seems inclined toward this explanation, too.
The notion of taking a flat piece of bread dough and baking it with a savoury topping is a widespread one and of long standing — the Armenians claim to have invented it, and certainly it was known to the ancient Greeks and Romans — but it is Italy, and particularly Naples, that has given its version of the dish to the world. ... Since then it has undergone a series of metamorphoses in base, topping, and general character that would make it hard for Neapolitans to recognize as their own, but which have transformed it into a key item on the international fast-food menu. [Ayto]
A pizza is manufactured, as far as I can ascertain, by garnishing a slab of reinforced asphalt paving with mucilage, whale-blubber and the skeletons of small fishes, baking same to the consistency of a rubber heel, and serving piping-hot with a dressing of molten lava. ["Simon Stylites," in The Bergen Evening Record, May 15, 1931]