fleur

Latin flos, floris meant flower. Old French made it fleur, and English borrowed it in the 1200s. At first, flower and flour were not just homophones — they were the same word, spelled the same way, meaning the same thing. The "flour" of wheat was its flower: the finest, purest, whitest part of the ground grain, separated from the bran and germ. Flour was a metaphor before it was an ingredient.

The metaphor was common across medieval trades. The "flower" of sulfur was the finest powder. The "flower" of any substance was its best, most refined form. Chaucer used flour and flower interchangeably. So did Shakespeare. It was not until the late 1700s that printers began distinguishing the two spellings, and the split was not complete until around 1830. Two centuries ago, reading a recipe would require context clues.

White flour — the flower of the grain — was a luxury for centuries. Brown bread was poor bread. White bread was rich bread. The industrial roller mill, perfected in the 1870s by Hungarian engineers, made white flour cheap for the first time. This was considered progress. It was also a nutritional disaster: the roller mill stripped out the germ and bran that contained most of the vitamins. Refined flour fed more people and nourished them less.

Today, flour is flour and flower is flower, and few English speakers would guess they were once a single word. But the old metaphor is preserved in other languages. Spanish flor de harina (flower of flour) still uses the phrase. French fleur de farine does the same. English just forgot that its two words were one and built a wall of spelling between them.