Five hundred years ago, the mark of a skilful baker was the ability to make a pie or loaf of bread with a hard, shell-like crust; refrigeration and plastic bags had not been invented yet, so a thick, tough crust prevented bugs from burrowing in, and kept the inside from drying out. It is not surprising, therefore, that English derived the word crust—perhaps via French—from the Latin word crusta, meaning shell, a sense that still exists in the name of the marine creatures known as crustaceans. The source of the Latin crusta, incidentally, was an Indo-European word meaning hard that also gave rise, through Greek, to the word crystal. The word crust appeared in English in the early fourteenth century and was followed a few decades later by crustade, the name of a pie made of meat, eggs, and milk, all enclosed with a crust. By the middle of the fifteenth century this new word, crustade, underwent a peculiar change in pronunciation, the result being that the word custard was formed. For the next 150 years a custard continued to be a meat-pie; it was not until the beginning of the seventeenth century that its recipe changed and custard came to mean a dessert made by baking a mixture of eggs, milk, and sugar, often served in a pastry shell. In the Middle Ages the French also had a dish similar to the original meat-filled crustade; they called it a croustade, deriving the name from their word for crust, crouste. English borrowed this French croustade in the mid nineteenth century as the name for a dish made by scooping out the middle of a loaf of bread and then filling it with a ragout. Earlier in the nineteenth century, another French word that derived from the original Latin crusta was borrowed by English: crouton, a crust of bread used to garnish soups or salads.
A dry layer of blood, pus or other secretion that forms over a cut or sore.
Hard coverings that result when exudate on the skin dries.
Dead cells that form over a wound or blemish while it is healing; an accumulation of sebum and pus, sometimes mixed with epidermal material.
The most prevalent definition of this term is the crispy or outer layer of a loaf, pie, or any other baked fare. However, when referring to wine, “crust” denotes the buildup of organic salts that wines discharge as they mature.